Don't do it for the money. If your Mrs. has a passion and a dream it will keep her (and you) going.
Don't copy another (successfull) channel, find your personality and your style. It will develop over time. Go back to the start of any channel and you will see, if they did not delete the old content, how crappy their content was in the beginning
Thai audience is quite big, you don't have to make your content in English. If your Mrs is charming and knows how to sweet talk in Thai, stick to your initial idea
Don't overthink it - go for it
Don't fall for Coaches that promise you to grow your channel in 6 months to 100k subscribers or whatever. Don't invest money. Every good advice you can find for free on Youtube if you do a bit of research
If you gain traction and exposure be prepared to read hate comments. Still 98% of the Thai audience are very polite and kind and will write positive comments, but there are a few that will get personal and they attack right there where it hurts the most.