It is upto you but considering his level of English understanding proficiency,I doubt he even understood half the words you said.We could convey the same point without assuming he's an idiot.
I'm not talking about what I'm saying, I'm talking about him seeing the words 'You are banned' several times and thinking 'Oh, I'll just make a new account! I am still allowed to be here'. Anyone that thinks that way is an idiot.
Provided, learning English as stated in my post,would help.
Admittedly, if he became proficient in English he would possibly be allowed back onto the forum and could be helpful. However, chances are that he won't. If this is the case, he wouldn't help anything coming back.