NaNa you are having a very trying time atm you poor sleep deprived women. I have not alot of advice for you as i cant begin to imagine what it is like. I bet you know why they use sleep deprivation as a torture technique in some countrys.
If you believe there is something physically wrong with him when he lays down then you are the one who would know so stick to your intuition and motherly instincts and take him back to a paed or even try a naturopath, they have alot of great calming remedies also that may help.
I hope things get better for you soon, i will be in Melbourne in a few weeks if you would like a NaNa nap i can watch him for you. I am sure Hamish and Aadi would have a great wrestle, they both are good at pulling hair and hitting, slapping and biting, oh i can imagine them.
Sending you billions of sleep vibes..........