Sometimes things happen for a reason and work out - he's happy where is he now and it will work well for him as he gets older. Would he be any happier in the old family home, with all his memories, in there on its own as some of the jobs and maintenance begins to get beyond him? Fair play to him for sorting this move - so many people leave it too late and cause hassle for themselves and their families by staying too long.
Some compensation sounds reasonable for the delay in payment so ask the company and see what they say first before going elsewhere. If they offer nothing then there's the financial services and pensions ombudsman to try next.
Doing your best for him now isn't really the extra few quid compensation though - he'll have his pension, the house sale money, the new pension from this - he should be fine financially. Given he asked you for this help he might be open to your support just ensuring that the money he has gets kept/invested safely and wisely and he has easy access to it etc - and encourage him to spend some and enjoy it.
The companies pension department/administrator are the only ones who've done anything wrong here - not you.