I believe my grandfather would benefit from rehabilitation, am I wrong to try and push for this?

Before you push for rehab, I would do additional digging. I mean this sincerely. I recognize your determination in your post and I can completely sympathize with your situation and that is why I'm cautioning you to really understand why they are suggesting that he isn't a suitable candidate for rehab. If you are right and maybe if they are just saying it is a temporary situation - then maybe you are right to push and ask them to reconsider. But there may be something that they just haven't told you yet that is driving that designation that it is important for you to understand.

Unfortunately we are are all too familiar with the home-hospital-rehab cycle in our family. And every single time we always saw improvement. Until the very last time - at which time my FIL was actually discharged from the rehab facility as "not rehabilitatable". A very big part of it was his mental/mindset. He was physically able to do it. But he absolutely refused to do the exercises. Refused to go to PT some days. And when he did, he refused to do the exercises. So after a while they just changed his status from rehab to nursing home and treated him as such until they discharged him. That was the only time he has ever been discharged from rehab that he did not progress back to at least where he was when he went in and came home worse off that he started.

They have certain criteria that they look at and decide whether a rehab facility will be able to help get your loved one to a certain level of mobility. If they know that rehab won't be able to help him based on his levels in the hospital there is a good chance they won't transfer him to a facility - at least as a 'rehab' patient, because they know that they won't be able to help.

At 89, he is almost at the age when most people approach the crude reality that life is not eternal. Falls and rigidity are some of the first signs of Parkinson's. Being slow to respond to verbal commands also goes along with Parkinson's. Furthermore, there is also the possibility of his having had mini-strokes over the years. I'm afraid that rehabilitation might not bring back your grandfather to the way he used to be. Parkinson's disease might be starting to take a hold on him. I wish I could be giving you better news, but the evidence suggests that his old active years are not going to come back. The hospital is not at fault. Serious health problems are common in his age bracket.

When you say "push for rehab", who are you pushing? The doctors or your grandfather? Even if the doctors recommend him for it, is your grandfather willing? This is often where our hopes and expectations hit the wall.

Aside from the good advice and wisdom from the other responders, your grandfather may be suffering from continued depression from the loss of his wife. There is a phenomenon called the Widowhood Effect: a "...National Institutes of Health study that examined more than 370,000 elderly married couples in the United States, researchers found that within the first 3 months after one spouse dies, the chance that their partner will also pass is between 30 and 90 percent."

source: https://www.uhhospitals.org/Healthy-at-UH/articles/2018/05/the-widowhood-effect

I'm only pointing this out because at his very advance age, you may need to adjust your expections for him. I'm sorry for the loss of your grandmother. May you receive wisdom for how to help your grandfather and gain peace in your heart during this journey.

It might also be wise to get a neurological work-up to evaluate if he indeed might have Parkinson's. He might have it, but was in early stages and the falls were a symptom. Parkinson's symptoms can be exacerbated by stress and also by prolonged inactivity, so symptoms are worse after the weeks of hospitalization. My husband with Parkinson's has had pneumonia twice, and both times his only symptom was fever and a major excerbation of his Parkinson's symptoms. Being slow to process commands can also be a symptom of Parkinson's--everything slows up, including movement, one's digestive system, and verbal proessing and verbal production speed. Physical activity is strongly recommended for people with Parkinsons, and indeed exercise is as important as medication. One other thought--a stroke or mini strokes can also cause Parkinson's symptoms. One way neurologists can test if symptoms are due to "regular" Parkinsons or vascular-related is to give the standard medication for Parkinsons, carbidopa/levodopa (sinemet). In any case, I would strongly push for rehab to try to get grandfather back to his baseline function as much as is feasible. Best of luck!

Has he had a chest X ray? My husband's weakness, falls and significant mobility decline was pneumonia. He didn't have any respiratory symptoms. A smart ER nurse spotted it right away. We learned his muscles were starved of oxygen. After a 5 day hospital stay he was discharged and we FOOLISHLY declined rehab. Never again, it was a huge mistake. Push for rehab. Best of luck; hugs to you

Push. It makes a difference for the quality of life for both your grandfather and his caregivers

CM’s questions are really important. Here’s another one. You say the “hospital won’t recommend it (rehab) because they say he isn’t a good candidate”. You are guessing why they are “making that determination”. You should be asking the full reasons why, and also who is making the decision. Perhaps you could ask Rehab to check him. It doesn’t sound as though anyone senior is involved with any of this at the moment.

I'd first of all push for a very much clearer explanation of what they think is going on. "Looks like Parkinson's but probably isn't" doesn't cut the mustard, does it - they're talking about someone who was independently mobile a month ago and right as a trivet not long before that. Ask what investigations have been done and what conclusions have been drawn, and try your best not to box anyone's ears.

Mind you, we're also talking about someone who lost his life partner in March. How is your grandfather coping with that, do you think? And how he is generally?