Feeding schedule

Hello, my LO is going to be 1 month on the 16th and he's starting to sleep longer now. I've noticed he is awake longer during the day, takes about 1 hour to 1 1/2 hours to fall back to sleep and then sleeps roughly about 2-3 hours at night. However, his feeding schedule at night has also changed. There are basically 4-5 hour periods between his next feedings and he will still be sleeping, which is awesome for us. One time it had gone over 5 hours. Our pediatrician had said to not let it go passed 4-5 hours and to wake them to feed. But he also mentioned to keep an eye on the poos & pees and his weight. My mom and other family members say to just let him sleep and he'll wake up when he's hungry. He was born 6 lbs 4 oz and is now 7 lbs 9 oz. He has normal bowel movements and seems content. He is breastfeeding and also given some formula when I can't breastfeed. I personally feel like I should just let him wake up on his own, but I don't know what to do. Any suggestions?