let me answer this question by posing another:

Ok hypothetically speaking, say you have a disease. (go with me on this, it applies directly to the situation at hand) Ok so say you had a disease, and there was no cure to it. You would die in exactly 6 months. Now say your brother (who broke the winshield) was completely clean of the disease but found a cure. Now the only way to cure the disease was to have unprotected intercourse with a dead goat. You did so, in order to cure yourself of all ailments. When something like this happens it puts everything in perspective, now does that winshield really matter? Now go further, say after you fuck the brains out of the dead goat in hopes of sparing yourself. You see your brother giggling because he made it all up. Would you make him pay for the winshield then? Now say you damaged the goat's inner rectum, and since it was dead, you couldn't heal it, but the farmer whom you borrowed it from had a written contractual agreement in which the goat must be returned in the same condition it was received. Would you give the mentioned farmer the broken winshield in exchange for anally deflowering his prize meal?
Food for thought