my experience as well. It’s the only hospital I have been to in Pattaya for the last 8 years and have always been spoken to in English and presented any documentation in 100% English.
Better safe than sorry, naturally. Great advice already given.
Just wanted to add that in 25+ years of going in and out of Thailand (and 30+ other countries) with prescription medication I have never even been approached about any, even when I was inspected.
I have used online notary for several different reasons and they are universally accepted now.
You do a Skype or FaceTime call to verify identity. You scan and email docs and they do the same in reverse with the stamp and letter of certification. Really easy.