Vets won't know.. you have to find out the countries requirements yourself and then instruct the vets to do accordingly .. bringing into the country is easy but your own country might require that you have extra vaccinations or an electronic chip inserted into the pet. As they are concerned that you may want to take your pet back home after it has been in Thailand for a while.. i brought cats here several years ago.. no quarantine here... flight costs are expensive for pets. You pay buy the animals weight.
You have family here who are Thai nationals.. and they are also blood relatives to you.... so i cant see why you couldnt have a non 'O' visa..( visiting family)
said is true for the type of passport i have. But im not sure that it applies to every nationality. . In the same way that not every passport holder will be given 30 days to stay if they have no visa.. permission to stay without a visa i believe is only 15 days for certain passport holders.. and im not sure whether this can be extended at immigration or for how long.
I personally cant see how they will accept anyone trying to extend a 'B' visa ( working visa) based on the fact that your no longer working (retired)
I would have thought you would need to get an 'o' visa.. and you would probably need to go to another country to get it. Then extend it here at immigration
So yes do get back to us and let us know how you got on.. be interesting to know.