extremely dry skin help


so my baby is three months tomorrow. over the past three weeks his skin has gotten EXTREMELY dry and it seems like nothing is working. I've tried Johnson & Johnson, eucerin, Aveeno, coconut oil, baby oil, and aquaphor. nothing will get rid of it and give him back that baby soft skin! we sleep with a humidifier on and always have and we moisturize him before bed and also when he wakes up in the AM. I don't know what else to do! any recommendations?