Hi, welcome
I haven't tried it, but at the very most, it will only help with physical misalignments/discomfort. It won't change any of his personality traits that make settling more difficult.
When you say you're having trouble getting him to sleep more than a few hours in 24, how many is he sleeping? I'm asking because at this age, most babies are still in a 'sleepy' newborn phase so if you're having trouble getting him to sleep and stay asleep at the moment, he could have pain causing an issue. How is he fed (breast/formula)?
To be honest with you, most people are still figuring out the routine at this point. If you keep at the EAS order, things should start to come a bit easier in the coming weeks. Keep in mind that A time is pretty much taken up with eating at this age, so a quick nappy change is often about as much as you can fit in between feed and sleep.
How are you getting him to sleep? He may sleep better in a sling/carrier where he's nice and close to you. Its good to start as you mean to go on, but honestly independent sleep is pretty easy to teach at 3.5-4 months after you've had plenty of newborn snuggles.