Even if a child has some kind of terrible disease, parents aren't stuck in the room with them 24/7. If going out for 90 minutes to golf gets him out of there and helps him clear his head, you can't hold it against him.
The issue is what's implied in all the criticism: the fact that a big part of us doubt Tuukka's excuse for leaving. I know he's not obligated to explain anything to anyone, especially if it involves his kids or wife's privacy, but he could make all of this go away if he just came out and said "my child/wife/parent has some kind of disease and needs to be attended to". But again, not our right to know. Just as a public figure with a history of flakiness, until he does that, I think people will doubt his reasons and question his headspace.