Agreed - letting them scream does not teach them anything, they are too young.
Have you tried lying down and have him sleep on your chest/stomach? This worked a treat for my baby (who is only 4 months old now) and he tended to sleep for longer too. For my daughter I use to lie on my back bring my knees to my chest and lie her on my shins (sounds weird I know) and bounce (gently) my legs. She loved it! And, it worked.
With the gas/wind thing, my mum taught me a trick......if they are white around the mouth, they have wind. Push his knees to his chest repeatedly.
Good luck, don't stress and sleep when baby sleeps.