Are in app purchases available for download on family sharing

No. From Which purchased content can I share using Family Sharing - Apple Support:

There are a few things that you can't share:

• Songs added to iTunes Match from outside the iTunes Store
• In-App Purchases
• Items that are no longer available on the iTunes Store
• Items that were hidden
• Apps that aren't shareable

The inability to share in-app purchases through family share is VERY disappointing and in some aspects makes family share useless. I've spent several years buying apps and in-app purchases mainly for my kids to use on my iPad. This year Santa brought my children their own iPad minis. After setting them up with their own iCloud accounts and installing the apps they each use they began asking me unlock the previously purchased in-app purchases. Why would I want to pay for these in-app purchases again?!?!?

Apple - PLEASE fix this!!!!!!!!!!!!!

There seems to be a work-around - a little awkward, but if it works, then you've got in-app purchases effectively shared! See How do I Family Share in-app purchases?