Yep I was born in Swansea, so the sea was a big pull for me too. I went to Hua Hin and Cha Am as part of my research (extended holiday tour!). I liked it all except the beach at Hua Hin. It's just huge, looks beautiful from a distance. But too big and very little shelter from the scorching sun. Across the Gulf here in Bang Saray, we have a lovely beach. Come and have a look if you get the chance. Some new condos too, but just a few so far!
It's a great plan. I got here in August aged 66 and I'm not regretting one moment. And your idea of waiting 6 months before deciding where to live is spot on. FYI I've chosen Bang Saray, lovely small town 25 Kms from Pattaya. Sorry I couldn't help on the visa question but I wanted to wish you good luck 🙌🙏
In theory he can bring up to 3 months supply. that's what I did. Reality is no one will ask or look. And in any case, any medication he needs will be ready available over the counter at most pharmacies