War with developmental milestones

Noah will be 9 months corrected age at the end of the month but his twin brother has surpassed him with tummy time and head control. Noah has been struggling. Don't get me wrong he sits up better than his brother and has better head control while he sits up but not on his tummy. Half of the reason is my fault and half of it is his temporary g tube that sticks out and hangs always tugging on him. He had bad reflux so we were always afraid to put him in a downward position. His gurd was so bad that even with his crib mattress being propped up; he would still projectile puke. Luckily his refulx medicine has managed it, but before his best friend was the bouncy seat!  He will probably sit up on his own before beating tummy time! Only time will tell!