Caught in a Lie or Misunderstanding?

I recently found myself in a tricky situation. My boyfriend said he was out with his brother, but I bumped into his brother at the mall while shopping for a birthday gift. It seemed like a huge mismatch, and now I'm questioning if he was really truthful about where he was. Should I confront him about this, or am I overthinking it? Any advice? #WhatWouldYouDo #TrustIssues #RelationshipDilemma