First, Son 1 and Son 2 will need their own unique AppleIDs - these being different to your own AppleID.
Golden Rule: Don’t share an AppleID between users. Each user should have their own AppleID for their own exclusive use - linked to their own primary email (and secondary/recovery email addresses and trusted telephone numbers).
Having ensured that you have separated your identities, as the family organiser, you can selectively share purchased Apple Services, Subscriptions, Apps and Media using Apple’s Family Sharing features:
Family Sharing - Apple
Set up Family Sharing – Apple Support
Share App Store, iTunes Store and Apple Books purchases with Family Sharing – Apple Support
How to create a new Apple ID – Apple Support
https://www.imore.com/how-set-up-family-sharing-iphone-ipad
So as to avoid unintended sharing and merging of your private/sensitive data (including Passwords) with your family, instead of trying to sign-out from a device that you intend to repurpose or give-away, it is essential that the device is properly prepared - and setup from scratch by the new owner (Son 1/2). To prepare the iPad for reuse, follow this procedure:
What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support
Proper preparation, as described, will avoid many other potential future complications and difficulties that might otherwise occur. After setting-up Family Sharing, you’ll be able to install your existing purchased Apps on devices that are within the family sharing group.
You may find this information to be helpful with setting-up an AppleID for a minor - and considering appropriate controls:
Apple for Kids - Official Apple Support
Help your child set up an iPhone, iPad, or iPod touch - Apple Support
Family Sharing and Apple ID for your child – Apple Support
Use parental controls on your child's iPhone, iPad and iPod touch – Apple Support