I would absolutely love to sing karaoke, but I cannot sing very well (thanks to being traumatized by my third grade teacher, who drove the love of singing out of me, by humiliating me in public) and I am rather shy. It looks like so much fun, but I could never bring myself to do it, although I enjoy listening to other people do it.
If you have the right venue and the right group of people in the right part of town, it can work out marvelously. I don’t know why, but in my town Asians, especially Filipinos seems to be drawn to karaoke. There’s whole sections of the Asian parts of our city that are full of karaoke clubs, way more so than in the rest of the city.
If your friend decides to open a club, have him do some type of surveying to find out the demagraphics for the folks who love karaoke.
Then don’t just have it be a karaoke bar (bars are a real turn off for me, the fact that karaoke is usually in bars and I don’t drink and don’t like to be around drunks or in dark sleazy places) have it be a restaurant that serves some type of themed food. Maybe it’s a tapas restaurant, or a small plates, or a place that specializes in fun, interesting appetizers and fun drinks restaurant or a burgers and dogs place with lots of interesting takes on burgers and dogs, or a fancy toppings pizza restaurant.
The place should have a killer sound system (maybe with some type of auto-tune ajustment feature for those who want/need it) and some big screens onto which you can project the singers doing their thing. Have great lighting, great ambience, great furniture etc. Make it a really fun place to be whether you are going to sing or not and they will come.
Possible name for the Venue (feel free to steal it) Oh Say Can You Sing? And have it be a restaurant that serves new takes on old American comfort foods like mac and cheese, burgers and dogs, fries and rings, meat loaf, fried chicken, egg salad sandwiches, grilled cheese, spaghetti and meatballs and peanut butter and jelly sandwiches.