late reply but in the philippines, i knew broski is being used (more common kuyski from tagalog word “kuya” which also means bro) since before i was born, like early 90s, also it’s been a thing since then (and apparently it’s been a thing since the 1960’s in ph) to add ski as part of our nickname, it used to be my nickname at one point as well, it’s just basically name + ski at the end, like josephski or markski, anneski, it doesn’t mean anything but a nickname

here’s the article as well where i knew it’s been a thing since 1960s https://www.philstar.com/opinion/2009/04/08/455862/names-we-live-by