I think my husband has postnatal depression

Since baby arrived my husband has been very low mood. Struggling to motivate himself to get washed and dressed. Rarely interacts with baby and opts to dothe practical things like make bottles, housework etc rather than baby related things. Always on his phone , even when holding baby, absolutely no interest in myself no interaction or cuddles. I'm getting really worried about how he's coping with the change in his life and our marriage , is so sad to see him like this ! He's just trying to get through the day everyday without enjoying the moments ,can anyone relate?