Walk Behind Lawn Mowers

My mom has a 22" HU775H walk-behind mower with the 111p02-0116-f1 B&S engine, purchased 2 yrs ago at Lowes. She recently loaned it to her granddaughter's boyfriend, and he couldn't get it started, so he and his father "worked" on it. They brought it back with a piece of the carb JB welded onto it, which of course didn't hold. I fixed the carb problem by cleaning the jets, but the piece they broke came off. I still haven't figured how they broke it. It is a crucial hole that the governor fits into, and it is broken off the carb body itself. Of course they refuse to pay for the damage, and a new carb from our local dealer is over 60 bucks! She is on a fixed income, and has a rough time. Is there any way U could help us out with a reduced price?