Can my friend extend a six-month multiple-entry tourist visa by making a U-turn to another country?

Repost: Hello guys, I need your advise please, a friend of mine has Thailand six months multiple stamped tourist visa. He has almost used up his 60days and he wants to go and make u-turn in another country by flight and come back to Thailand in order to get an extension of another 60days. Can be do that with this visa or he should just go out and get new sticker type visa? He said someone told him that stamped visa is old model and it is no longer acceptable