ESA - income related or contributions based

Hi,
I'm writing on behalf of my dad.
He's been claiming CESA - Support Group since he was made redundant 4 years ago.
He's also been getting PIP daily living enhanced rate for roughly 18months
he lives with my mum who is NOT on the ESA claim as the woman said she didn't need her details.
Mum also not working.
My question is, shouldn't he be on income related ESA after 365 days?
Should they both be on the claim as a joint claim which would mean couple rate payment not single rate payment that he receives now?
also is he entitled to any premiums? 

They have both worked for over 30 years and the benefit system is just mind boggling to them so any help would be much appreciated.
thanks in advance.