The partner might be a veteran and the surviving spouse may get nothing. The sytem is pretty complicated. It depends on the status of the veteran. eg if the veteran is Gold Card TPI or EDA, the surviving partner would automaticallky receive a War Widow(er) pension fron DVA refardless of the cause of the veterans death, If the veteran dies and his cause of death can be related to service or cause of death is a DVA accepted condition then the partner will also get the War Widows pension. If the veteran is GoldCard (but not TPI/EDA) or White Card or no card and the cause of death is unrelated to service then partner is entitled to nothing.
You national licence (you do not have an international licence - it is an international drivers permit (IDP) which is not a licence at all. And you need a medical certificate.
You may also be asked for proof of your accommodation. Also it is not a 60 day visa or a visa of any kind. It is a 60 day Visa Exempt stamp that Immigration put in your passport.
You are correct. However your national licence, supported by an IDP is only valid for the 90 days while you are a tourist in Thailand. Once you have a long term visa of 90 days or longer or are on an extension of stay, then you are no longer a tourist and are required to have a valid Thai licence.
Firstly, you do not have a visa of any description. You have a "visa exempt" stamp in your passport which is not a visa. It sounds like you have entered Thailand many times using this method and want to stay lonmg term in the country. The visa exempt entry is intended for tourists and not for long term stay. At some point soon Immigration will deny you entry into Thailand. You need to get a long term visa from outside of Thailand related to the reason for your stay in the country.