If he's fed, dry, burped, not gassy and tired I would try white noise. My favorite is the hair dryer. Puts my kids out in minutes. GL!
Alsi, if your LO is gassy I do colic tummy massages and colic calm.
The hair dryer is a miracle worker. There are some pretty good apps on your phone that simulate a hair dryer so you don't burn yours out. Make sure it's as loud as possible!