Help! I'm Not A Promoter, But I Need Some Professtional Promotional Assistance!

I would act as a referral person only. You refer him to the agency/promoters of the venues you think fit.
You may go as far as helping them with English, but it has to be untainted 1:1 translations only and not negotiating for them.
You can add in a request to open for him, but you need to do this with the agency not the guest artist.
You can ask for a “business referral fee” which here in Europe is up to 15% of what the artist gets, but largely depends on how they could have booked him without you.