god, i was going to start a similar topic!!!!
i think it depends on each families life, hours of work, family help etc. for me i find i have such a good routine with the kids when my partner is working. we go out, do things, dinners on the table for him coming home, we have fun but when he's home evereything seems to stop. we barely eat a meal (the kids get fed) but it seems to be a struggle to russtle up something. we just cant get into working as a team when he has so much time off work
but with his job he can sometimes only work a few long days a month or can work 2 whole weeks a month. so he is home a lot and thats when i expect him to do stuff.
i also work for myself and went back 2 months after having a section but an example last week, i got up with them, got them ready, went to work then when i got back he went to bed!!! when i'm still recovering from a tonsilectomy then getting bronchitis
i had a section in febuary and me and the little one ended up sleeping downstairs so my boyfriend could get sleep!! i got my tonsils out a couple of months ago, he went sailing a few days after and left me ill and home alone with a baby and a 2 year old when he knows i have no family around to help me out when ill, i was bouncing off the walls i was that dizzy. my partner sounds quite like your brother in law. he has only washed our youngest and he's 8 months. and it wasn't till i knew i was getting a section that he bathed our 2 year old for practice for when i wouldn't be able to lift them !!! the list could go on