If xah didn't see his children, he couldn't post his ski photos with them on Facebook. If they didn't stay with him for part of the summer, people wouldn't say 'what a wonderful father he is'. He sees these visits also as what he gets out of the arrangement, and he wants to have a good time. The children are somewhat resentful because they sometimes feel that he isn't doing things to make them happy...he is doing what he does to satisfy his own needs and desires...
I think it is right that as an alcoholic/narcissist, he sees the children as an appendage to himself who can sometimes satisfy his ego and help him put on the appearance that he hasn't abandoned them.
But truly, if he can't be bothered to go to their graduations, buy a thoughtful gift, vacation where they'd like to go, make sure that they had enough food on the table, arrange to be near them and know them...then he really has abandoned them.