"He's got work" so? This is SUCH bullshit!
As if mothers are doing nothing in the day!
Op you need to talk to him and explain that you're BOTH parents now that parenting especially at the moment when baby is so young is VERY tiring so you BOTH need to pull your weight on parenting and that includes BOTH doing night wakings.
If you're bf obviously you do the feeds but there's NO reason he can't do his share of nappy changes, winding, cuddles, teething duty.
It wasn't mil's business to interfere BUT as always with in law issues you have a spouse problem really - he didn't HAVE to listen to her! In fact I'm really wondering if he hadn't 'primed' her to say it!
Chances are mil is round my age or not necessarily much older (46) in which case I'd genuinely be shocked if her husband hadn't done any night wakings with their DC. Even my dad (now in his 70's) did them. Both ex and my father were in the army when their DC were newborns - doesn't get much more demanding!
"My DH works from home so didn't even have to drive to work." Ffs! Absolutely NO excuse then!
Bigbluebubble - I seriously don't know why you've stayed.
"It's not an issue around modern parenthood. My DH did his fair share of night care over 30 years ago, and he wasn't in any way unusual. Why do people on here constantly assume that anyone over 50 was bringing up their children in the 1950s?" I too find this bewildering. As I said my dad did his share of broken nights and is now in his 70's, I was born '72 not '52! And mil is very unlikely to be very much older than me. Certainly not likely to be older than my parents! My grandparents (who DID have their kids in the '40's/50's) one grandad didn't do night wakings but he wasn't the greatest husband/father anyway, other grandad didn't do every night as he worked shifts so wasn't always there, but when he was there he did and depending on shifts he would do stuff on days off too.
"Do some men literally never talk to their friends or other men with children to find out how they cope?" Like calls to like. The type of men to think this is ok behaviour tend to have friends who think likewise.