I’m curious why you feel you need to eat more fat. If fat in your diet makes you feel ill in various ways, maybe your body is telling you something.
If your concern is that are getting too skinny and need extra calories, there are other ways to eat more, sugar and refined starches being two options. These aren’t nutrient-dense foods, but most fats aren’t nutrient dense either. (Adequate protein is also important, but I’m sure you know that already.)
What really struck me about your post is that you are often wheelchair bound. I feel for you. I imagine that regaining some strength is probably about your number one priority at this point. If exercise is truly impossible, and your muscle is continuing to waste away, I hope you’ve talked to a doctor about your options. Honestly, in a condition like the one you describe, you might think about anabolic hormones. I know they’re sometimes prescribed for people who are wasting away, such as patients with AIDS. Maybe they would help you (literally) get back on your feet enough to start exercising and rebuilding strength. Just a thought.