Firslty Id be telling him how he may not care about cars, or have passion as we do for them but that does not give him the right for someting like this to happen then not have the common curtisy to even offer to clean it up let alone say sorry.
Me, personally Id be having VERY strong words, my ex tipped an entire kerbab in my old car, I made her pay for a valet.
Shold of seen her face, but she got the message, no food ever came in my car from that day forword.