Prince William is expected to be a ‘tough’ monarch when it’s his time to rule, an insider has claimed, and it could have consequences for his brother Harry. The heir to the British throne will become the role of enforcer when he takes the big seat, a source has said, and it could be trouble for Prince Harry. Prince William‘s difficult relationship with his younger sibling is no surprise, with the Duke of Sussex talking about it multiple times throughout the years. From spilling the beans with Oprah Winfrey to writing previously-guarded secrets in his bestselling memoir Spare, Harry hasn’t exac…