I would reccomend Kuala Lumpur, whe I applied for a further tourist visa a few years ago the process was very easy, but remember you do not get the visa until 9am following the day you apply.
You should have said that in your initial post ! Well he needs to get the right visa then, go on to the UK Thai Embassey Web site, marriage visa, I think everyone assumed he was 18 !
Be wary of these people who say they can do the Driving licence for you, its a scam, and like others have said it has nothing to do with visas, Its easier if you have an international driving licence, which you should have for Thailand anyway.