I can't claim to have known XY very well, but nonetheless, he always seemed like a cool guy and it makes me sad to hear that we won't be seeing from him again.
Its always a scary thought that someone may pass away and yet we might not know about it, but I'm glad that we do know instead of spending months wondering where he had gone, so I guess I'm grateful for that.
I was never good with these sorts of things, because I never know what to say, but I guess it will suffice to say that I wish his friends and family the very best in this situation.