On one hand, HOAs are great. You never have to worry about your neighbor
storing a 1970s travel trailer or other unsightly junk in their yard.
OTOH, you might be restricted from running a generator to keep your pipes
from freezing. So the $64K question is, will the HOA even allow the
install of a buried propane tank and a generator?
Another consideration is that if power outages are a problem for your friend,
they are likely a problem for everyone in the HOA. With member support,
maybe the HOA could install a community propane tank and amend it's rules
to allow individual generators? If not, your friend is screwed.