I live in Asia and let me tell you that this is absolutely a thing, I have seen it countless times.
For anyone suggesting that he is taking advantage of the girl I can assure you that nothing could be further from the truth. 'Bar girls' are absolutely notorious for this and there is a well established system in place that they use to extract money from men like this.
I can 100% guarantee you that he is not her 'boyfriend' and nor is he the only one that she is doing this to. It is very, very, common for these girls to have several men on the go at once, all sending her money from overseas in the hope of having a long term relationship, or even marriage.
The excuses and the begging will start. Her family will have a poor harvest (she is from Issan, I guarantee it, a poor agricultural region of Thailand where families routinely send their daughters off to the tourist hot spots to work as 'bar girls'), her buffalo will get sick, she won't have enough money this month to pay her phone bill, or her rent. Can he please help her out.
Many of these girls have kids (at home with the family on the farm) and are often married to a local man.
Let me reiterate this happens all the time.
There is a Reddit sub where you can read all about it
www.reddit.com/r/FarangsofPattaya/