Probably, but it could have a binding and sudden release factor that may appear as an instability.

I do not know as I have not seen him.

The turning of the tibialis on the femur can cause binding of the joint that appears as an instability. If the joint is simply lax due to Wikipedia reference-linkmeniscus problems then this will not be the case.

If the meniscus is damaged, then what about a brace?

Hope that this is helpful.

Best regards,

Neuromuscualr.