As far as I'm concerned, the man deliberately, with premeditation,  killed his wife.  He handed her a fully loaded gun with which to play Russian Roulette.  There was no doubt if the outcome, especially in her state. What would we say if he had handed her the keys to the car, told her to go for a drive, and she ended killing not just herself, but others in the road?
Nor should he or his family have the children.  His family spirited the kids away to Texas, then immediately sought custody and in the process, lied  significantly by omission in order to get it.   Now they are far away from their mother's  family and in danger by the fact that their father has access to them.  He killed their mother and through the underhanded machinations of his family, has been rewarded with essentially free access to the children, telling them lies about how their mother died.  The children should be returned to Alaska as soon as possible. Both he and his family have proven they are unfit for custody.