Whoa..rephrase your question..if the choice is between living comfortable in a nice senior care facility, or living shabbily in a basement..without any amenities or care..when it's his pension paying for it..and he''s incapable of making an informe decision..that a whole other question...we don't know..."Care" could mean feeding him three times a days..no more...we don't know..
Why do you assume he lives shabbily? That's my problem with this "question" of yours. A converted garage is an apartment? My stepson lives in a converted garage and it's gorgeous.
Trouble is.... you're making the whole thing up. It looked to me like a very nice home, and nice family.