Ipad lost mode activated

bought ipad from a family member, after buying it i realized he left all of his info in it so i fabric reset it. After i restore it , it activated lost mode. The person who sold it to use is and older guy and has a whole diffrent icloud on his iphone. Which is not linked.

But im sure the ipad isnt stolen cause i literally saw his icloud and all of his info, that was the reason i restore it

he doesn’t have receipts but since he was the owner, if bring him to apple with me, is it still possible to fix it?