this has been a problem for a while now but for a few nights running he was really good waking at 6:30am anyway he’s now got back to the 4am wake up. We’ve had really bad wind and snow so could it be the weather that disturbs him? Or could it be he can hear my rabbits outside they’re in a big enclosure and run freely in there? Or could it be he’s going through the ‘terrible twos’? Or has he gotten into the routine that that’s his toilet time? Often when he wakes at 4 mum gets up to him barely speaks to him tells him to go toilet and lets him outside then tells him to get back I his bed and returns to bed herself she does this because she’s worried that he’ll go to toilet in the house and that he’ll wake the neighbours, is it best just to leave him completely at this time? He doesn’t bark just scratches the door and mum happens to hear him.
I do the same as your mum. My dog goes through periods of waking up during the night wanting to go out. Sometimes for a poop, sometimes just to sniff the air. I can't sleep if he is restless so I'd rather get up let him out and in again less than a minute later then I can go back to sleep easily.
We found our boy was waking with the sunlight and wanting out. We woke but let him wait 5 minutes longer every two or three days until after a few months when we had him staying in bed until we woke, but he was used to being second place to the baby being changed and fed first.