Who goes to Thailand to become a Buddhist?? Now if I were going to secretly become a Muslim, I might pick Thailand. How long was he in Thailand?
Actually, Buddhist studies are a major part of the tourism scene. There are many temples which teach foreigners particularly. Wat U Mong in Chiang Mai has a good number of German and English speakers. Anyone speaking Thai can become a monk at most any temple.
I heard he was there for a month