Where can I find a stroke specialist to examine my mother in hospice care?

I would start by asking her doctors or medical team. It sounds like you're specifically looking for a specialist who does home visits (a rarity, indeed, but not unheard of.) See also:
How do I get my parent's doctor to give us complete and honest information?

See all 185 questions about Hospice Your mom's hospice team should know who does this in your area, and be able to make referrals. You can also check with a geriatric case manager (someone with experience in managing hospice care may be most helpful.) The Eldercare Locator is a good place for finding care managers. Finally, you can check with the local offices of the American Heart Association or the National Stroke Association (numbers can easily be found online; add San Francisco to your search) and ask for their advice. Best of luck.