Non OA multiple can use nearly 2 years If you come back in 1 day before expires with 1 year insurance you will get stamped another year But in that case, if you want to go out, you need re entry permit because that stamp is single entry
You will need a new certificate of residence and new medical if you cannot do within 30 days That's what they told another guy when I was there last week ..
I know in Phuket have nursery homes, like we call in Belgium "service flats" or "residential care center" at much cheaper prices and more service ( have more staff and time to take care of you )