Parental passcode

A few months ago, I had setup an iPhone 7 for my son, using parental controls. Unfortunately, I cannot remember that four-digit passcode I setup. But I am also unable to access the section for AppleID, iCloud, etc., because this field is grayed out. This only became an issue tonight when my husband tried to make a parental change on the phone, but neither of us can get past the screen time login. We have exhausted every possible combination we can think of. I would greatly appreciate any and all advice. This has me frustrated to no end. Thank you!