Found this list thought it was useful 30+ MoneySaving Tips & Discounts for Disabled People - MSE (moneysavingexpert.com)
The council tax disregard is probably the least known about. My friend's father's probate grant was held up slightly by the insistence of his local council (who only found out he'd had dementia when she informed them of his death) of asking for a copy of his letter of diagnosis so they could repay all his council tax from that date, about six years previously. The family hadn't asked for it, and were very surprised to receive a cheque for over £12k. My mate was unable to find anyone among her friends who'd heard of it either; I thought I was reasonably clued up, but I hadn't. It's particularly helpful for people struggling to pay for additional social care for a parent who hasn't been awarded enough council-funded hours and only has a low income.