Vientiane is over 170 meters above sea level. A rise of 60 meters in sea level will mean that most of central Thailand will be under water but the Korat Pleateau will still be dried. Not only will Bangkok (a mere 2m above sea) be under water but most ASEAN's capitals will also submerge except for Vientiane and Naypyiadaw.
If the central part of Thailand is under water, most of southern Vietnam and Cambodia will be also under water. On the other hand, the Korat plateau and Isaan may still remain above sea level.
However, if the Isaan region is also under water, most of Laos along the Mekong river where most Lao people live will be also under water.
South East Asia were covert with the sea last 50 millions years ago. Pacific Ocean water had moved torch to South then curved throughout Indian sea and pushed Himalaya Mountain from 1200 miles North of Argentina to where it is locating right now. This was real happened last 50 millions years. Next 500.000 years, Japan will gain 80% more new land growing from its coast today to 800 miles West torch to China and will shrink Japan sea to 5 miles wide in between Japan and China border line. Japan sea water will go swallow 1/2 of South East Asia countries.