Thumb Sucking

I let my son sucked his thumb until he was 4 years old. But I slowly wean him off by telling him to only suck when it's nap time or sleeping time when he's around three then just two weeks before he turn four, I told him to try stop sucking thumb completely since he already started going to school. And he really stopped by himself within two to three days. Many people told me to put medicated oil as they think that it's not good for kids to be sucking thumb but I don't feel safe and it's good that our LO can self soothe. Can try pulling the thumb out once your LO is in deep sleep. Yes, your LO will suck their thumb again when they're slightly awake in the night but can try to pull out whenever u see your LO is in deep sleep again.