Why is Tricare not paying for our elderly father? whats best for our father?

Our elderly father is at this particular nursing facility which is really expensive but offers the proper medical treatment he needs for his trach etc and he has great DR nurses etc here, I was told that his insurance Tri care which was helping us for about a year, is now stating that they will no longer be able to to cover his expenses, they say he is stable but he really isn't, so in the end he’ll have to move back home which is nice and all but I know me and my sister will not be able to take care of him cause he really needs 24 hour treatment plus this happen before and it didn't turn out well thats why he's in this facility(another story) I don’t know if tricare will pay for his home care but my sister said are only option is we pay out of pocket (which can’t afford) or for our father to use Medicare I thought Tricare was the best insurance? I was told that if we went through these particular insurances like Medicare that they could come after everything he owns including his house and everything else he owns is this also true? what would be best for our father?