How do I care for a parent (91) who no longer shows interest in getting up and participating in life?

My dad passed away two years ago after being after being seriously ill for four...needing 24/7 care... ( my parents had moved close to me in 2007) ...my hubby and I moved our bed to their house and I took care of him until he passed. He was a month shy of turning 88 and 2 weeks shy of his 60 wedding anniversay)) Through all of this mom, who is 5 years older was doing pretty good. She had had bouts of TIAs no outward lasting effects ... She had always been the type that saw the glass half empty.. Months after daddy passed, she had a long TIA.. Episode.. We had home health and OT etc..through the last two years she has been in and out of hospital and rehab ... UTIs sinus infections..flu.. She is still able to use a walker with help but is so fearful of falling as the day progresses.. I imagine a type of sundowners as she has more anxiety..sometimes inconsolable in afternoons evenings..she has brain atrophy typical of a 94 .. Almost 95. Has blood pressure issues and was diagnosed with CHF last year.. It has been tough for her..so hard not to be able to do.. I take care of all her needs. But she can feed herself, clean her face. She is scared of going out of the house now.. Course the winter kept us indoors.. I hope we can get out on the porch as the days continue to warm up. The thing is she is so tired, tired of trying tired of eating, tired of drinking... She dwells on these things. I too wish I could figure out how to help her to have the best quality of life at this stage in her life. I Can tell her all day long to look at the beautiful day, pray, see the birds..be happy at what you can do... Relax
Sigh some days it's not so bad... Other days most days...it's all I can do not to argue about what she perceives is so terrible. I get so sad that I can't help her to help herself be happy. We get through the days though..some days are better than others... All I can do is encourage and praise.. Not easy😊...
I guess what I am saying is we can't force them to see our point of view that there are still many joys still to enjoy to make our days happy or at least peaceful... All we can do is be a light for them ( not easy arghhh, I fail most days!) try to stay joyful, maybe when you go to vist your dad, read that book on the screen... Call your brother and sister before hand to prepare your frame of mind.. Kind of have a plan but be prepared to throw it out the window depending on his mood... Does he still walk? If so..encourage him to take a walk with you outside.. If he's in bed.. Just sit by his side... Bring him some of his favorite foods..although he may turn his nose up at..maybe ask your brother and sister what he does like. Foods my mom loved ..she doesn't care for and also her teeth make it hard for her to chew...
Call him and leave him messages if he doesn't answer.. Even if it is a one sided conversation.. 2 minutes make a huge difference..
Keep trying...try to keep your emotions in check...breath and be joyful... Same with your mom..make time for yourself away from all your responsibilities ..even an hour can help. Can stress enough time to take care of you!

It is hard letting someone go on to be where they are. All you can do is provide love, companionship within an ulterior motive, and support when needed. If you are inclined to see if something interests him, keep those activities in alinement with his interests: a model or an airplane he used to fly to put together, books on vintage planes he used to fly~ things that tap his rich history to ground him a bit. Good luck and always know you can only do so much: your dad is the author of his life at whatever stage he is in.

I do want to salute all the caregivers on this forum who are caring for an elder in their home. Not only do I believe that all of us caregivers will receive a reward in heaven some day, but I believe there are even more special rewards for those who are providing full-time care for a loved one in their own home. My mother used to say: "Just do the best you can." and certainly that is what each of us is doing. I also try to live my life so that I will have no regrets later.

Even if he never seemed to really care for it, he might like to listen to music or songs from his youth? My mom will sometimes sing along to familiar tunes. Also, you may want to ask about the meds he is taking. As others have said, you should not feel responsible for the way your father feels and acts. It is difficult to see your parents change. My mother loved books and literature and she now only glances at the pictures on magazines...Take care of yourself