Answer: I think he didn't do the right thing because well i mean, George did not do the right thing at the end of the book because I believe Lennie still had a reason for living and that should not have been taken away from him. There were plenty of other solutions to Lennie's problem than killing him. I also think that George should not have given up on his and Lennie's dream, I think it was 100% possible, if George had allowed it to be.
Step-by-step explanation:
I hope this helps. I really think he shot him in love though because he didn't want lennie to be tourched in a room full of special kids and George knew how much Lennie was a danger to people so he just shot him, but I still don't think it was right for George to shoot him..