My great Grandad's medals, still in the little cardboard boxes with wax seal, were in my Dad's loft.We had a very similar situation, a relative sold off our Great Grandfathers medals which included 1st and 2nd Boer War and WW1 medals without any consultation of the rest of the family. They appeared again years later on ebay but were too expensive for myself and my dad to win the auction. My dad did eventually get in touch with the final purchaser to ask for first refusal if he ever sells them on but we are not that hopeful of a good outcome.
He rented the house out to the son of a friend; turned out to be a real waster. Medal boxes still in loft.
I saw the medals (and some 1950s Richmal Crompton "William" books with an uncle's name in, inscribed as birthday presents) in the local indoor market. Seller was outraged at the suggestion he was selling stolen goods; threatened to call the police because I was slanderous (!). He calmed down eventually when l named the waster, obviously realised he'd been dealt a raw hand; waster was then in prison and well known locally. Took the goods off him with a grudging hand shake.
One of the things that really pissed me off was the stupidity of the thief. In the original packaging, with letters, the medals were worth ten times the value of them on their own. Ah well.