We are trying to get mom (89) to drink more fluids and eat more but she doesn’t eat a whole lot, maybe eats about half. What is going on?

She's 89. I think that says it all.

Yes, there is always that 'fear' that our LO's are approaching the end of their lives and it always catches us by surprise.

Daddy had Parkinson's, but his appetite to the 'almost end' was always fine. When he began to vomit after small meals, we knew the end was beginning. I was surprised that he could maintain life on basically popsicles, which are just sweetened water!

Daddy entered palliative care which then gently segued into Hospice. He had a month or so of being pretty stoned on Morphine/Valium and it was honestly a BLESSING for him to pass.

We never forced anything on Daddy. Let his desires be our guide.

Bless you in this time. Read up on mom's conditions so you understand what is happening in her body. Don't add 'miracle meds' or have unrealistic hopes.

Linda, your mother isn't active; she doesn't need as much food anymore.   Alva is right on the money in assessing the situation. 

Give her foods that are nutrient rich, and 1/2 of what you have been giving, but experiment in portions to find what really suits her needs at this time.    You might also consider a supplement, such as Ensure Plus or Boost.  I can't remember for sure but either of those were recommended for my father, in his late 90s.

This is more or less normal at 89. Especially with her underlying conditions. Her heart pump is weak. Please look up congestive heart failure so you understand the weakened condition of her heart pump, and how it plays into all other systems including her already injured lungs. Does your Mom have her wishes in place for her last years? Doe she wish to have palliative care now? Or Hospice? You would be surprised how little food it takes to sustain life in the elderly. VERY LITTLE. Do see if she will accept one multivitamin per day. Don't force fluids in someone with CHF; the heart has a hard time pumping fluids through to do the exchange. Speak with her doctor about this.
Wishing you good luck. What you are describing is not abnormal for one with your Mom's condition, and at her age. Wishing you best of luck.