I have obtained DTV with medical treatment as I am suffering from type 2 diabetes. Before granting DTV, I was asked why do you apply DTV instead of Non O medical treatment visa? I said it is lifetime treatments. I have to travel there as doctor's treatment plans.
Malaysia has one thai embassy and 2 Thai consulates. If you decided to apply there, thai consulates are advisable than embassy. Consulates are in Penang and Kota Bharu.