My dd was going through an early phase last month, and I tried everything I could possibly think of, including later naps, earlier naps, shorter naps, longer naps, earlier bedtime, later beditme, etc.!!! I finally tried wake to sleep, which I think did help. At the same time, I was working on her room as well ~ she has asthma, so we added a HEPA humidifier, removed all stuffed animals, etc. I recall your ds has had health issues as well, so you might want to check out his room. But I would definitely give wake to sleep a try: For 3 days, go in 1 hr before (so 3:50 in your case) and gently resettle (if I wasn't careful, I would fully wake my dd and that would be it, so be careful ~ when she was just 1 year, I had to much more solidly wake her, but not this time around). Even though you have 3 bad nights of sleep, it's certainly worth trying.