Bangkok bank advised me that a will was the only way if your deceased.
Also If living you'll likely need to provide the power of attorney document, along with proof of the person's hospitalization and inability to communicate.
On re-entry you get another 60-day VISA EXEMPT but its up to the IO to let you enter. You may be questioned why so make sure you the 3 important requirements to enter.
its NOT UP TO YOU but up to OP. The DTV isn't 3 months but 5 years and he never mentioned 3 months (90-days). Please read about DYV and make YOUR SUGGESTION TO OP.
฿1900 for the 30 day extension. If you choose to do inside Thailand have everything prepared and go talk to your local immigration. Then submit the required paperwork