I think a lot of members on here are against CC on a young baby, so I'm not sure if you'll get much advice on that front. However, have you tried the pick up/put down method?
My DD (almost 6 months) would only go to sleep for a while if she was rocked in her moses basket. Obviously, as time went on that became increasingly difficult to do as I already had back problems and it was too heavy to do for 15 minutes at a time. So one day, I just said I wasn't doing it anymore. So I tried pick up/put down (or at least my own version of it).
I lay her down in her cot when she was settled and due a nap. Walked away. She'd begin to cry, I counted to 10 seconds each time (just incase she'd resettle herself), then walked over, picked her up and rocked her until she was settled again (not asleep, just content). And repeat. The first time it took around 30 minutes, but eventually I put her down and she just dozed off. It will take a while for this to work in the long term, but it's really helped our DD as now it only takes a few pick ups on a bad day before she's asleep. Sometimes none at all.
I'd try this first. I'd also recommend having a process of elimination before bedtimes or naptimes. For me, I made sure that:
- all naps and night-time sleep happened in the same place
- the room was dark and had white noise on (if anything, just to minimise the noise of us walking around outside the room)
- she'd had her feed for that time of day/the day
- dry nappy just beforehand
- if she's teething, a bit of teething gel on her gums
- the room at the night temperature for her and her sleeping bag/blankets
I'm sorry if this sounds like I'm pointing out the obvious, but sometimes it only takes one little thing to stop him from drifting off. At least when you've went through everything and you're keeping it consistent, you know he's just fighting his sleep rather than something else bothering him.
By doing all of this I also managed to stop needing to feed to sleep, too. It's almost worth having a few tougher nights and resolving the niggles like feeding to sleep, etc, than needing to do it later on down the line. I also found a dummy to be priceless, although I know a lot of mums are against them. It's a personal choice- it just helps our DD sooth herself without needing a bottle 24/7.
Good luck, though! I know how tough and lonely those sleepless nights can be, and it will get better. x