Sounds more like the guy just managed to get over his ex and "get back out there".
How much of that was due to the fact the girl liked him already (Women don't generally invite single guys over on their own unless they have at least some interest in them, or are already good friends) and how much was due to his "swagger", "DHV", "negs" and "kino" is up in the air.
That is one of the biggest misperceptions in the mainstream: that PUA is about using negs/DHV/kino. the reality is that most good methods will emphasize that a decent part of this is a numbers game and simply about talking to enough girls. That in itself is a skill.
As an example, my results shot up significantly when I went from talk to 1 girl every 4 hours at the beginning to 5-10 an hour. I happen to try and find a girl who naturally digs me than one who needs convincing.
How much of that was due to the fact the girl liked him already (Women don't generally invite single guys over on their own unless they have at least some interest in them, or are already good friends) and how much was due to his "swagger", "DHV", "negs" and "kino" is up in the air.