Sounds like the dreaded four month sleep regression. It hit us really hard.

Do you think he definitely wants to feed when he wakes? Ignore me if you've already tried, but would it be worth giving other settling methods a crack first before offering boob? Cuddles, rocking, bouncing, singing - or get Dad on the job, so little man doesn't smell your milk? For the last six weeks I was feeding DD every two hours overnight but realised that we'd both got into the habit of doing it; I started stretching the night feeds out again and try other techniques first if she wakes under the three-hour mark.

Ignore the 'solids make them sleep longer' idjits.

I'm sorry Charlotte, it's really rough - especially with two. I hope his sleep settles down again soon hon.