8.5mo sleep all over place, 3yo (and us) shattered. Help?!

[SouthernComforter]

8.5mo has never been consistent but currently he's waking for the day between 4.45 and 5.15am. What can you do at that time? Mostly I try to feed him back to sleep or cuddle/wrestle with him for an hour on the mattress we've put on his floor. In the end he always wakes the 3yo.

Mostly the baby has at least one feed in the night (last night it was three). I struggle to get him back without feeding. Does he even need it? Ewen the sheep does sweet FA.

Baby is quite dribbly (he's got 4 teeth already) and pulling himself up and crawling. That's partly why I struggle to get him to lie down in the cot. He eats well.

Baby now needs first sleep of the day at about 8am while 3yo struggles with behaviour cos of tiredness and me and hubby trudge through each day. I've got a kit day at work today and dreading it.

Any advice? I can remember 9 months being bad with DS1 but not sure for how long. Should we do some sleep training - if do, how?

Generally I think treating the early wake up as a normal night waking is the way to go. However if he's waking the 3 yr old, it might be best to leave the room with him.
My DC1 was always an early riser so we ended up distracting her with toys until she was old enough to amuse herself with something. Grim, but there was no getting her back to sleep.
DC2 on the other hand seems content to sleep until 6/7am thankfully. Although has plenty of night wakings at the moment

Sorry that's probably doesn't offer much in the way of help!