I'm looking for ideas and resources about training a dog to help older people around the house. I know that some service dogs are trained to hold things, pick things up, open doors, etc. I'm fuzzy on the details, though, and I feel like I might be missing some obvious tasks that a dog could perform. So far, the main task I can think of would be picking things up off the floor so they don't have to bend down to get them. Of course, if the dog could be trained to open jars, that would be really helpful, but I imagine there are some anatomical obstacles there.

But is it possible for a dog to...I don't know...find someone's glasses for them? Help them keep their balance? (In my experience, they are better at throwing people OFF balance, lol.)
I'm also wondering if there are any good books specifically about training these types of tasks. I read quite a bit about operant conditioning, but I see no reason to reinvent the wheel if other people have already come up with solid protocols for this stuff. I'm just not sure specifically what I should be looking for. Is there a name for this? Or a specific type of training that would be similar?
This is a dog that is going to be a couch buddy anyway, so I figure since she is there, she might as well help out around the house. Seems like a win-win.
Any information or advice would be most welcome. TIA!