There is a old place home in Pashupatinaath. I don't know your case but they mostly take helpless people and some people there have been living there for a long long time.
This place gets some of funding from Mother Teresa foundation, hence have a lot more volunteers too, working to help the residing people. There are some disabled people too. As there are various kind of disability, I can not say for sure if this will be the place you would be looking for your brother.

Good Luck in finding a better place.