PIP claim, brain injury, failing managing at home

My adult son is on ESA (Support Group) as a result of brain injury to frontal and occipital lobes requiring emergency surgery 20 years ago. Lives alone, major executive functioning problems, though manages basic elements of daily life (cooks for self) but has difficulty with reading and making financial decisions, has constant physical pain (back, neck leading to sleep problems). He has MAJOR problems keeping flat clean and tidy and coping with chaos which restricts capacity to have friends, socialise. Can perform specific functions like cooking, personal washing but cannot manage preparation to get to that point (planning) on time - also with going out and managing appointments. Lives chaotic depressed life late at night because he is so slow getting round to do anything throughout the day. Suffers ffrom lethargy, delaying decisions through the day. No-one there to prompt him. He refuses to have visitors because of the condition of his flat - this exacerbates his mental state and isolation. Would it be worth claiming PIP? Claim forms only recognise washing and eating as necessary functions - keeping a person's living environment clean and habitable seems not to be part of personal independence, worthy of PIP.

Thank you. I realise that you can't give advice about claiming. I suppose what I'm wanting to know is whether there are, in general, any circumstances beyond personal care/hygiene and cooking/feeeding - i.e. maintenance of a habitable environment - which count as essential constituents of personal independence which fall within PIP law. If someone can wash and feed themselves - although in the overwhelmiing chaos of an unkept flat which create mental stress - is that acceptable under PIP criteria? It is never referred to in the questions asked in the claim form as far as I can see but is a huge barrier to livng an independent life. Sorry if this sounds repetitive.