You should have chewed him out for not checking to make sure the gun was unloaded before he cocked the hammer.
Remember the old adage, "The Gun Is Always Loaded until you check to make sure it is unloaded".
Anyway, I'm going to strongly suggest that on these guns with easily removed barrels that you do so before cleaning them.
I'm assuming the Renegades are like TC's other guns and have a hooked breech.
Even if they don't it isn't that hard to remove a tang screw and a barrel wedge (or pins).
Had you removed the barrel and the nipple and dunked the breech into a bucket of water. Then using a wet cleaning patch on a jag, pumped it up and down in the barrel until water flowed out of the muzzle, you would know the barrel was unloaded.
Then when he tries to blame you for his own screw up you could say, "No Way. That barrel had nothing but air and rust preventative oil in it when it left my house."