I'm going to be honest with you. I've had liquid cooling in my computer for just over a year now. Unless you really see yourself as loving to tinker with your computer, don't do it. At this point it is just a hassle for me. Every time I need to drain or refill it, I just feel like scrapping this computer and going back to aircooling. I wish I had never done liquid cooling. This is not to say that liquid cooling is bad. Some people really love it and it does offer significance overclocking room. But it is not for everyone. Eventually, you just want to sit down and use your damn computer instead of worrying about leaking fittings and refilling the loop.
It seems you friends dad would not be the person to want a liquid cooled system.