PCL,ACL and LCL recontructive knee surgery

Hi

My son is about to undergo what I am told is a major operation to his knee following an injury last September.

He has to have a complete knee recontruction because the LCL, ACL and LCL ligaments are all torn.

Can anyone help with respects to recovery times, mobility after the op, and ongoing, what his mobility might look like?

Any help with this would be much appreciated.