Beware!Cant share it with family members on apples family share

I upgraded to scanner pro through this app and it turns out that, even though its features have been unlocked for me to use, I cant share it with a family member. This is the message I got when I contacted the developer "Please note that the upgrade to Scanner Mini allows you to use all the functionality Scanner Pro has except for Family Sharing - this is according to Apples policy and as much as wed love to help our hands are tied here."
They are blaming this on apple but its the very first time this happens to me.

Marandi1973 about Scanner Mini – Scan PDF & Fax, v7.1.2