Koh Samui is way over rated was ruined decades ago. But if you enjoy thousands of foreigners and Burger King and fantasy land Thailand you will love it.
Been there many times and was always enjoyable. Far fewer scams, much cleaner than Thailand, very few if any loose dogs, and far fewer foreign trouble makers.
Malaysia in many ways I prefer to Thailand. Also I noticed they tend to have higher quality foreigners. And certain countries are banned from entering. I can,t help but wonder if that thins out the riff raff.
Lucky if I meet two a year and have lived here twenty four years. I understand there are more out there but not many. Happy that your friend is willing to make an effort to learn. Would you like me to make a video for YouTube proving my point? Foreigners who are fluent have asked the same their hunch less than 10% . My guess about 1% if that.