I need help deleting my sons Apple ID he no longer has an iPad and I need to remove him from my family

If your son's age is listed in the Apple ID as less than 13, you will not be able to remove him. Apple only allows children to be moved to another Family Sharing group. You'll need to contact Apple Support for assistance in removing the Apple ID from your group.

For more information on deleting his Apple ID permanently:

How to delete your Apple ID account - Apple Support

Note that, even if your son no longer has an iPad, if he has other devices such as an Android phone or tablet and your are subscribed to the family versions of Music or Apple TV+, he can still access those. So, unless you need the slot, you may want keep him on Family Sharing.

Remove from Family Sharing:

Leave Family Sharing - Apple Support

Delete Apple ID (this will remove all data associated with the Apple ID permanently):

Understand and control the personal information that you store with Apple - Apple Support