This is the best advice. Tell them to take a couple of programming courses. Give them some simple projects like drawing a Mandelbrot set. Or more seriously,

This is the best advice. Tell them to take a couple of programming courses. Give them some simple projects like drawing a Mandelbrot set. Or more seriously, advise them to do something other than getting a PhD, such as getting a Master's in 2-3 years and taking a couple of computer courses along the way.