The psychological literature documents that men date quite soon after a death much more often than women, and that it’s not actually unhealthy or avoidant in most instances. That for some people, this is part of the way they grieve. The thing that can be unhealthy is that children and in-laws can feel that it’s a poor reflection on their father’s true feelings about their mother. But when you’ve just lost one parent, you’re not going to risk alienating the other - even teenagers often put a pause on teenage rebellion with their parents for a number of years after a death. They’re taking out their anger at their father on the LW.

And I notice that the father has done nothing to shut it down, so I think this relationship is doomed.