Would that actually work though? An ED visa is extended every 90 days, they aren't a 12 month visa. His multiple entry may expire after the first 90 days and have to be renewed each time.
Also if you rent a home and move it's a good idea to update them too. I updated both lots of details quite recently with SCB. Only a 5 minute job so well worth it.
No, once you have all the paperwork from the school you would need to travel to a neighbouring country to get an ED visa. Many people choose Vientiane in Laos as it is close, cheap and easy. You can travel there by bus or you can fly.