well, how long have you been friends, is he A REALLY GOOD FRIEND that you DONT want to lose. If so i would suggest 50/50- because you didnt have to take the money he gave you, you couldve said you dont want to be responsible for it. but at the same time it was HIS CHOICE to have you send it. i suggest calling the president of UPS and complaining till they do something about it. but as far as who is responsable, both of you are, since it was your friends choice to have you send it that actually makes him 51% responsible and since all you did was send it (no other proof of anything else) that leaves you with the other 49% responsibility- in court you wouldnt owe shit but lawyer fees, but if you wanna keep your friend and make good, tell him you'll give him half of what he lost and tell him not to ask you to send no money for him, you shouldve known the risk of sending it in the mail and stated that YOU ARE NOT RESPONSIBLE if it gets lost, in the same sense he shouldnt think that you should be responsible, but some people are like that. i know if i trusted a friend to ALOT of money, that means if he says ups lost the money , than they did, and he dont owe me shit. but thats me and thats a REAL friend, not many people have those.