To think you don't call or refer to your parents-in-law as Mum and Dad

[PocaMiseria]

One of my brothers calls his wife's parents Mum and Dad. We come from a close family and our parents are still together ..... I find this weird and disrespectful to our parents.
DB's wife calls our parents Joe and Freda.... I call my DH's parents Bob and Maggie (and he calls my DPs Joe and Freda) and our sister also uses given names rather than "Mum and Dad" for her in-laws.
AIBU ? I would hate for my kids to be calling another woman "Mum"!
(The idea for this question came from the thread about step parents being called Mum and Dad....)

My parents both called their in-laws Mum and Dad. I don't even know if there was any discussion, it was usual for people of their generation. I have a vague recollection that my Grandad called my great-grandparents Mam and Dad, although this might be a wrong memory.

I called Exdp's mum by her name if it was impossible to avoid, but we never really decided what I should call her.

I’m not married, so refer to dp’s mum by her first name. If he’s talking to me he will say for example ‘mum said could you....’. If I am talking to dp I will say to him for example ‘mum said can you turn the heating on’, I do that with his siblings too. With his nieces and nephews I will for example say ‘Nan asked if you will pop the kettle on please’. I don’t know why I do this? It just happened naturally. I’ve never thought about it to be honest. (By the way she did say I could call her Mum, which I only do when I am drunk🙈).

My wife is from another country. We both call her parents Ma and Pa, I felt like her family had really accepted me the first time they signed my birthday card "love Ma and Pa" especially as being openly gay is much more unusual where they are from.