The sentence should be:
"What made Naresh the butt of ridicule among his friends? His helping mentality."
In this context, "the butt of ridicule" means that Naresh was the target of mockery or laughter. While "helping mentality" generally refers to being generous or willing to assist others, in this case, it seems that his eagerness to help may have made him an easy target for his friends' ridicule, possibly because they took advantage of his kindness or mocked his behavior.
