Travis from MWOD staff here. Since it is likely a joint issue, there shouldn’t be any problems with flossing the knee and ankle to improve how the muscles are sliding over each other. When doing the knee avoid wrapping over the kneecap. Wrap just above the knee cap and up, I like to use box squats and light deadlifts to move the knee through some ranges of motion. I would also have him box squat and try to keep his shins vertical and stop him around parallel to keep from any undue shearing at the knee. Deadlifts should be good as well as long as he has a good hip hinge. I think it is smart to avoid the plyos at the moment, too much margin for error.