Hi Salsam.
The $400 is only for room and board. Medicare (mostly) pays for care and medications. In-home hospice care is very common, and that's where family shares the burden of care. There are plenty of other home-type facilities that aren't dedicated only to hospice and they offer varying levels of care.
Dementia is, in my opinion, the worst way to go - I'm sorry to hear you had to go through that with both parents.
I can't say with authority how dedicated hospice facilities handle it, but I'll see if I can get Monica to reply to this message with more detail.