Maybe try a gradual approach, very slow, at getting out more than once a day, maybe this can help you see him even if it isn't as many times as he would like, cause you need to think of your well being, do you think he would understand this and not be dissappointed? Like pace yourself out, not letting yourself get to a uncomfortable level in the 3d, but at the same time trying to spend more time outside of the home.
I do not know your situation too well to make suggestions like this but these are some things I myself would try if I were in your situation, it is rough when one hates to refuse helping someone they care about, but you need to consider how much of an effect sacfificing your time may have on you, take it in stride. I am sure your friend wouldn't want you to do anything that may cause you any setbacks, so see if you can explain this to him.
Just my 2 cents, meanwhile I think you are a terrific friend to this person to have done the things for him, and being supportive to him, that is such a beautiful thing

((((((((((((((((((((( Chris ))))))))))))

Take care,
DE

In giving advice seek to help, not please your friend
SOLON