I got my ED visa in Vientiane end of Feb without any problem. Mine is Uk passport but I donβt have much travel history to Thailand on my passport fyi. Make sure you have to make appointment online.
you might have to apply for the ED visa in SA if he is holding a SA passport. I am Hk passport holder and I recently got mine done in Hk. My school told me that these days the Thai govt is quite straight / changing their regulations. It is recommended to apply the ED visa at the country where your passport was issued. You can try it at Laos but may not get approved.