Cradle cap

My son has awful cradle cap, he has lost almost all his hair because of it. I know it’s because of over production of oil on his scalp. So the question is how often should i be giving him a bath/washing his hair? I try to wash his hair every other day but I’m between days he gets sooo scaly and it looks god awful. I know they say it doesn’t itch or bother them but I’m pretty sure it itches my son cause he scratches his face and scalp raw. Any help or suggestions are appreciated! 💕💕