The man who mows the grass for the church next door threw a rock while mowing & completely busted my passenger window out, I did not see it happen, but I seen the grass freshly mowed & my now shattered window.
I don’t know who he is & can not talk to anyone about it until tomorrow, is he legally responsible for replacing it?

It can be referred to the Church’s insurance carrier, and it will be up to them.

From a legal standpoint, you would need to prove negligence. This was an accident, not an intentional act, so that will be difficult