Some suggestions needed
 

My 13 year old arranged a mall trip with his father tomorrow. I really don't want my son in his dad's vehicle with his father driving. Any suggestions how to approach this subject with my son?

I would drop him off at the mall at a set, make sure that your hubby is not stoned, and then set a time to pick him up.

Minor modification ......

"NO. Your father is not healthy or in his right mind right now and it's not safe for you to be in a car with him. He is a thief and if he steals something at the mall with you there, you will both end up in trouble and in JAIL. " Seriously, what if daddy steals something from a store to sell for drugs?!

No is a complete sentence. I suggest you start setting some serious boundaries about the kind of people you allow in your life and around your children. I know you don't want to accept this but you are letting your son go to the mall with a drug user and a thief! Since when did that become acceptable?

Your teenage son is a witness to all this....