what would you do?

i have a friend that gets shitty if you input your honest opinion without completely disagreeing with him. he seriously has anger issues. he has gone through multiple phones and even broken his steering wheel in his truck because his phone wasnt working properly i guess.

my question is, he has a coolant leak in his truck and he knows this but isnt giving it any attention. so his truck is on the line of blowing up. i want to ask him if he is going to get it fixed but fear that he will retaliate and defend himself in a way that makes it seem like i am questioning his wits and im done dealing with this kind of behavior of his but with it being his truck on the verge of blowing up.. what would you do? ask him about it and then feel like you shouldnt have even asked about it or just ignore it and see what happens in the future