Q: No ask to buy option

Hi Heelstone,

Welcome to the Apple Support Communities!

I understand that you are having a couple of issues with Family Sharing not working the way you would expect. As far as your son being an adult, it sounds like his Apple ID may have been created before starting Family Sharing. The process to create an Apple ID for a child happens in the iCloud settings as described by the article below.

Family Sharing and Apple IDs for kids - Apple Support

iPhone, iPad, or iPod touch with iOS 8

Use these steps to create an Apple ID and add the child to your family group:

1. Go to Settings > iCloud > Family, and tap "Create an Apple ID for a child."
2. Enter your child's birthday and tap Next. The birthday for a child's account can't be changed after the account is created. Be sure to enter the correct date.
   
3. Review the Parent Privacy Disclosure and tap Agree.
4. Enter the security code for your credit card and tap Next. If you don't have a credit card on file, you'll need to add one.
5. Enter your child's name, tap Next, then create their Apple ID (username@icloud.com) and tap Next.
6. Follow the onscreen instructions to set a password, choose security questions, and set up your child's account. Choose passwords and security questions that you both can remember.
   

When a Family Sharing group is created, it automatically creates a shared family calendar.

Family Sharing - Apple Support

Now it’s easy to be one of those organized families.

Family Sharing creates a family calendar where everyone can view, add, or change events and appointments, and they can also get an alert when something changes. And anyone can use the Reminders app to send time or location reminders to the family. So when it’s picture day, pizza night, or just a trip to the beach, everyone’s in the know.

Cheers,

Joe