All situations call for different reactions... as a bartender I can tell you all about it...
I'm still just a student.. but I don't see what he did as wrong... the fact of the matter is, unfortunately, if the boyfriend wants to get in, he will it's just a matter of determination, and using youtube... theres even high security bypass techniques... Man I hate that... but what he did really is just the same as changing all the pins... he knew the lady could not afford a complete re-key... so he made one pin longer, and cut the existing keys to compensate, if anything to get on him about, is the fact that he could have charged more for his time/work/callout... I'll remember this... GOOD FIX MATE!....makes me want to do this to my rental unit... just for piece of mind...