Since every person is different, there are no rules about what to do or say, but here are some ideas that may help. Keep them involved in their care. Don't do everything for them or make all their decisions.
Nobody likes feeling helpless.
Have them help out around the house if they can. Everybody likes to feel useful. They want to be part of the group, contributing what they can. Include them in the household. Make them part of normal talk about books, TV shows, music, what is going on around the world, and so on.