Protected person status and assets test

My mother and father were married for a number of years (around 30), but eventually separated and divorced, with my father leaving the family home. After only a few years, my father returned to the family home. They have both resided here since then, although still ‘separated’. They are both listed as joint tenants on family home.

They are both on full aged pensions (separately)

Although separated, they are extremely close.

My mother may have to enter a nursing home soon, and it’s my mum and dad’s wishes that he continue to reside in the home. Since they are legally divorced, obviously he’s not classified as a partner for protected person status, but he was providing a level of care for her. Would I be right in saying that he can be classified as a protected person as her carer (even though he wasn’t receiving a benefit for this)?

If he is not classed as a protected person, would half of the family home value be calculated as part of my mum’s asset test? Assuming it is, and assuming that determines there is a fee to pay, how would that work if she physically can’t pay the fee? Eg, it’s more than the pension she receives. Would my dad be forced to sell the house?

So I live with my Dad and am his career. I also work full time because we could not survive financially if I didn’t. So I’ve never tried to get carers status. Recently his health has deteriorated and I’m concerned he will need to go into care. If I understand the definition, I’m not a protected person?