While I can understand T's feelings, he is ultimately in the wrong. There is little that brings out the righteous fury like working hard on something that you are proud of, and then getting less than the positive response you expected. Thus, his reaction is appropriate vis-a-vis the expected reaction of an alive stuffed bear with little professional experience who has just received an artistic cockblock, but it is hardly admirable.
To insist on your artistic superiority to the detriment of the client's wishes, whether or not it's a friend, is an unprofessional attitude. But this is part and parcel of T's character, no? He is inside of his own head, and artistically driven to the point where he cannot actually apply his talent to any real-world execution. We've seen this many times before. See: the drum set, the Microsoft-is-a-burger-bar-in-1950s-Texas* dream sequence, etc.
Beef shouldn't have lost it at him, but he's not the supposed "professional" here, and the dude did insult his family.
*I may have gotten every fact about this setup wrong, as my attempt to locate the comic for links turned up squat on all points. But you know the thing I'm talking about, right?