A physical collision is not the only possible cause of damage.
Both aircraft would have been travelling at around M0.8 pushing a shockwave in front and dragging wake turbulence behind.
At a closing speed of up to M1.6 depending on relative course a close encounter could do a lot of damage, especially to the smaller aircraft.
ATC in most of africa is a joke and something like this was just waiting to happen. At the speeds involved there would have been little chance to see and avoid.