Get a Uk address. Ie your son or daughter. You need a non-0 retirement visa , 3 months. Get it on line ok. When you get here You can get 12 month extension. You need a bank account. The. Get hold of the Thai visa centre. ( I can’t write too much here but pm if you need more info )
Only you know if it’s real. ! If you can rent for a while whilst you look be good idea. But don’t be put off by the negative comments here. Only you know if she is for real
I am just telling you how it is , this has been bought up many times. The immigration officer feels he is using a visitors visa to stay here long term , and had no doubly told him to get the correct visa if he wants to stay here long term .
If you are saying you are staying 90 days then leaving for a few days and coming back in for a further 90 days each time for a year. No wonder , it looks like you here permanent. Which is not a problem if you have correct visa. You are taking the piss with what you are doing