Why would being old mean he must have'suffered greatly'?
Horrible people don't suddenly turn into innocent paragons of virtue and love on their 65th birthday. They're just older horrible people.
It puts me in mind of my mother. Violent and abusive in her teens, twenties, thirties, forties and fifties. But once she got the white hair, suddenly she's seen as a lovely little old lady.
Strange how she still went for me with a garden implement and giggled at my pain (luckily she missed taking my eye out by a whole inch - got a massive shiner, though). But to others, oh, no, she couldn't possibly have meant to do that, she's a sweet, dear, little old lady. Bullshit. She just had another tool to use to get away with it when she said 'no, of course it was an accident, it just fell three feet upwards, flipped horizontal and travelled five foot through the air to get me in the face'.
Same way that wifebeaters don't suddenly become innocent little old men or murderers don't become unreproachable non murderers on the day they pick up their pensions.
Bad, uncaring, violent, neglectful and abusive people become bad, uncaring, violent, neglectful and abusive old people when they get old.
So there is no reason to assume that an absence of grief, remorse or culpability in anything means anything more than they don't feel any of it, irrespective of their age.