Stubborn cradle cap

My son is 15 weeks old & STILL has cradle cap. I’ve tried everything but it keeps coming back. Baby oil, avocado oil, coconut oil, vegetable oil, Vaseline, I’ve even rubbed Crisco on his head, been using dandruff shampoo, I apply deep moisturizing lotion on his head everyday. It literally clears up for like 4-5 hours & then BAM!—he’s flaky again. I’ve talked to his doctor about it & everything she’s prescribed & suggested doing can’t keep it away.

Family members keep making comments about how bad it is & keep asking why I’m not doing anything for it but I’ve tried just about everything.

What else is there to do??