I am a Live-in Caregiver for my father who has Parkinson's. What can I expect as he progresses?

Here is the website for Michael J Fox's Parkinson's support and information organization. They have a lot of resources for patients and caregivers. I am concerned that your own health has a disability related to mental health. Get help sooner rather than later!
michaeljfox.org
From your description, sounds like your father is in STAGE 4.
Here's a copy of the stages and progression from another website.
Parkinson’s disease (Parkinsonism) is marked by the presence of certain recognizable symptoms. These include ncontrollable shaking or tremor, lack of coordination, and speaking difficulties. However, symptoms vary and may worsen as the disease progresses.
The main symptoms of Parkinson’s include:
uncontrollable shaking and tremors
slowed movement (bradykinesia)
balance difficulties and eventual problems standing up
stiffness in limbs
Many doctors who diagnose this brain disorder rely on the Hoehn and Yahr rating scale to classify the severity of symptoms. The scale is broken into five stages based on disease progression. The five stages help doctors evaluate how far the disease has advanced.
Stage 1 is the mildest form of Parkinson’s. At this stage, there may be symptoms, but they’re not severe enough to interfere with daily tasks and overall lifestyle. In fact, the symptoms are so minimal at this stage that they’re often missed. But family and friends may notice changes in your posture, walk, or facial expressions. A distinct symptom of stage 1 Parkinson’s is that tremors and other difficulties in movement are generally exclusive to one side of the body. Prescribed medications can work effectively to minimize and reduce symptoms at this stage.
Stage 2 is considered a moderate form of Parkinson’s, and the symptoms are much more noticeable than those experienced in stage 1. Stiffness, tremors, and trembling may be more noticeable, and changes in facial expressions can occur. While muscle stiffness prolongs task completion, stage 2 does not impair balance. Difficulties walking may develop or increase, and the person’s posture may start to change. People at this stage feel symptoms on both sides of the body (though one side may only be minimally affected) and sometimes experience speech difficulties. The majority of people with stage 2 Parkinson’s can still live alone, though they may find that some tasks take longer to complete. The progression from stage 1 to stage 2 can take months or even years. And there is no way to predict individual progression.
Stage 3 is the middle stage in Parkinson’s, and it marks a major turning point in the progression of the disease. Many of the symptoms are the same as those in stage 2. However, you’re now more likely to experience loss of balance and decreased reflexes. Your movements become slower overall. This is why falls become more common in stage 3. Parkinson’s significantly affects daily tasks at this stage, but people are still able to complete them. Medication combined with occupational therapy may help decrease symptoms.
Stage 4: Independence separates people with stage 3 Parkinson’s from those with stage 4. During stage 4, it’s possible to stand without assistance. However, movement may require a walker or other type of assistive device. Many people are unable to live alone at this stage of Parkinson’s because of significant decreases in movement and reaction times. Living alone at stage 4 or later may make many daily tasks impossible, and it can be extremely dangerous.
Stage 5 is the most advanced stage of Parkinson’s disease. Advanced stiffness in the legs can also cause freezing upon standing, making it impossible to stand or walk. People in this stage require wheelchairs, and they’re often unable to stand on their own without falling. Around-the-clock assistance is required to prevent falls. Up to 30 percent of people at stage 4 and 5 experience confusion, hallucinations, and delusions. Hallucinations occur when you see things that aren’t there. Delusions happen when you believe things that aren’t true, even when you have been presented with evidence that your belief is wrong. Dementia is also common, affecting up to 75 percent of people with Parkinson’s. Side effects from medications at these later stages can often outweigh the benefits.
The progression of Parkinson’s disease is most commonly evaluated by motor symptoms such as muscle stiffness and tremors. However, nonmotor symptoms are also common. Some people will develop these symptoms years before developing Parkinson’s, and some will develop them after. Anywhere from 80 to 90 percent of people with Parkinson’s disease will also experience nonmotor symptoms.
Nonmotor symptoms include:
cognitive changes, such as difficulties with memory or planning, or slowing of thought
mood disorders such as anxiety and depression
sleep disorders such as insomnia
fatigue
constipation or urinary incontinence
vision problems
speech and swallowing problems
difficulties with sense of smell
Nonmotor symptoms may require additional treatment in many people. These symptoms can advance as the disease progresses
My mother-in-law is now in skilled nursing facility due to needing a catheter to help with urinary incontinence that caused UTI's, urinary tract infections, that made her unable to move or communicate. Get a home health evaluation from your father's doctor and get plans in place now. Things can change very rapidly and no two patients respond the same.

In my experience, you need to plan now for his next step and continuing decline. I know everyone has a different experience with PD, but the changes can happen very rapidly. The more you have in place, the easier it may be to deal with those changes and/or crises. Then just do what you can at the time, and be ready to implement changes to his care.

Sooner or later his needs will become greater than you can handle, it is wise to be looking ahead to that time. If our elders live long enough they eventually reach a point where their body or mind (or both) start to fail, deciding just how far you are willing to go is a personal choice. Advanced PD is marked by physical deterioration and may also include parkinson's dementia, as I'm sure you know. So, looking ahead are you willing to provide assistance with dressing? Bathing? Toileting? Are you comfortable being his advocate with health care practitioners? How many years do you envision giving to his care, and what will you do if he still needs you in 5 years? A decade from now? What about going with lack of sleep if he needs you through the night, or lack of personal time if he can no longer be left alone, will you be able to cope with that?

Don't wait for a crisis to explore and use whatever supports are available now and in the future, and always have a Plan B.

When will it be time to get home health or AL?

When careing for him becomes too difficult. Don't try to be a "hero" and in the process, ruin yourself. It's happened to many of us.