Can dads get pp depression?


I know they aren't necessarily postpartum but is there a form of it that dads can get? My SO has been extremely down on himself since our baby boy came.. I've never seen him like this, we've been together 4 years.. he never feels like he's doing enough, helping enough, loving enough.. he's been an amazing daddy he's so protective and exceeded all of my expectations as a first time daddy.. I keep trying to reaffirm that but it doesn't seem to be helping.. anyone experienced something similar with their SO? Is this normal? Should I encourage him to go to the doctor? I'm at a loss here..