To think DS can walk in pjs in the evening?

[pjdrama]

DS (4) goes to his dads every weekend at 7.30pm

His bedtime at home is 7.30-8.00

I therefore have been sending him ready for bed in pjs when his dad collects him. It's a 20 min walk.

Receieved a text stating "it's unacceptable, it's not the 80's, I'm fuming when people sneer at him" etc along with a long list of instructions as to suitable attire and a demand I pay cab fare if he's already in his pjs

AIBU to have thought I was doing a favour having him ready for bed?!

Pj not PhD!

I wouldn't if he was walking - what if the pyjamas got dirty? Or he may be cold...

It sounds like you are both passive aggressively try to assert control over each other, by focussing on clothing at hand over times.
Get a grip for the sake of your dc.
It seems to me that because you are sending him in pjs, your ex cannot send him home in 'mum's home clothes' and that's why the farce of changing clothes when he gets back to yours is insisted upon.
Not judging, but wonder whether you smoke, and ex is making an issue out of wearing his clothes at his house.
Please sit down and try to reach some sort of agreement to make this hangovers less tense for your dc.
Personally I think it's a bit grim and totally unnessary to put dc in pjs for the walk to dad's. Surely your ex just changes him into his house pjs when he gets there?

*handovers