They are safer in their crates, especially since he is still young. Like you said, you wouldn't want him to jump out of bed. Even if he didn't have the bad leg, jumping off things at an age under 1 year old is not good for them as their growth plates have not hardened yet. This can cause permanent damage to their bones. We let ours sleep in their crates at night and when we are gone from the house. It's a safe place for them and they enjoy staying in their crates as it becomes their own space.