The loss of a kid is nothing to sneer at and it affects some people differently to others. I have some friends who lost a child during pregnancy 10 years ago and they still celebrate the child they nearly had and they still grieve. Not everyone is as tough as you.
His behaviour hasn’t changed since he lost his child. This behaviour is exactly in line with how he’s always behaved. You can excuse changes in behaviour after a traumatic event, continuation of existing behaviour is a little harder to excuse.