400.000 Baht will not evencover the basic treatment for Leukemia, went through and now in remission( for last 12 years) total cost was 13.5 million baht and took almost 1 year. Ship him back to UK.
Here is a copy of a "living" will I got from a friend who had it made up after an other friend had problems getting a life support machine turned off. I think this is what you are looking for..
Living Will English.doc