It sounds like his carer was/is unfit to be his carer, so lots of links broke in the chain here. If you 're in council housing because you're vulnerable, you are probably going to be less able to agressively advocate for yourself, and clearly his carer was useless in that regard too.
My sister in law is in the US and works for an agency related to social care and she is assigned vulnerable adults like this - her job is to make sure that they aren't falling between the cracks the way this man has and to make sure that they know what they should be getting and helping them advocate for it.
Heads should roll in the council team responsible for this though, on a number of scores.
Even if you look at it coldly, if I owned and was renting out an apartment building and had hired a management agency to handle the maintenance and tenancies, and this happened, I would sue them for EVERYTHING. Not just the abuse of the tenants, but the severe damage to the building. It's appalling.