I'm not familiar with someone getting banned from AdWords because of the issue you describe. Spammers use adwords. You might be referring to Adsense where he would put ads on his site to make money. That's a much more tough environment.

I think you are trying to help him advertise his business on AdWords so his ad is placed on Google and possibly other sites, correct?

He probably has a really low quality score at this point.

These are things you want to look into:
Make sure his max cost per click is high enough.
Make sure his daily budget is high enough.
Use the key phrase you are bidding on in the title and description when possible.

Google will tell you what they recommend the cost per click should be and what the daily budget should be. See if you are close to those numbers. If it's too much money consider targeted phrases that aren't as competitive