I heard through the grapevine that an ex-employee of mine (left the company a few months ago) was in a car crash recently. We were always close and I was sorry to see them leave. Would it be strange to get in touch with them and ask how they're doing? I heard they were uninjured and are back at work (and in fact have seen some ex-colleagues at an industry event at an industry event a couple of weeks ago) but I imagine they were shaken up (I was shaken up when I heard about it...). I really cared about this employee (and I think they knew that) but I obviously don't want to disturb them at their new job (we're in IT sales so probably wouldn't see each other otherwise as there tends not to be much crossover between sales involving different companies).