He broke his foot last year, and tore his meniscus the year before. It's not that his body is weak. I am sure S&C strengthened that for him. But once you suffer an injury, you are just more likely to have the same injury or a different injury involving the same limb due to odd mechanics.
In case you haven't read the article I linked. I'll quote:
"ACL injury was linked to a successive injury of the same ACL, and other injuries in the LE. HS was associated with subsequent ipsilateral HS and knee injuries. Previous achilles tendon rupture increased the risk of an analogous injury on the contralateral side. An ankle sprain was associated with a re‐injury of either the ipsilateral or the contralateral ankle. Post‐injury changes were present in strength, proprioception, and kinematics, which may have led to overall changes in motor control and function."