Ok, first, I would like to thank you all for the fast replies and for thinking with me. 🙏
It looks like the better option is to apply for a visa beforehand. Because my parents are older i dont want to burned them with the process so I will try to figure it out with your help hopefully.
I am looking into visa agencies- which visa agency would you recommend and does it make a difference when their place of residency is different from the passport they hold? (For picking an visa agency county based)
interesting- so it’s not considered an extension- immigration will however will give my parents 7 days to exit and they have to pay 1900 baht, correct? Is there a name for this ( giving them 7 days to exit)?