I feel like a single parent

I had a baby 4 weeks ago and my SO although is the most loving protective dad to our son isn't really pulling his weight with the tasks.

When he gets in from work he'll have a cuddle, but he won't feed him, change nappy (has never changed one even though I've tried to prompt him to) doesn't tend to him when he cries and I'm out of the room, has never changed his clothes etc.

I feel like I may as well be a single parent but I don't know how to mention it to him kindly without sounding like a bitch.

A couple of times I've shouted at him when the baby has been crying and he's just sat there. I'm finding it really difficult.

My MIL said to him, "What happens if Rose needs to go into hospital overnight or needs to go out for the day and you don't know how to do anything?" And he shrugged and said "It can't be that hard"

I asked him to change our sons nappy and he replied 'im not in the mood'

It's so frustrating, but I don't want to come off as horrible when I mention it to him.

How can I approach him