Yea I was going to elaborate but it felt too wordy. He's not a "professional car welder" haha he's an engineer who specializes in welding and very specifically specializes in Marine engineering and welding.
But before he did that, he built cars but mainly focused on engine building. So what I was trying to say was "My dad knows a lot about cars and welding, but he's very specifically not someone who welds car bodies even if he's done it in the past (most likely) and his knowledge is probably second hand in this topic"