My son died his hair black in Oct. Now his role in the musical requires blond hair. His director says this should be no problem, but our hairdresser says it is a 2 to 3 step process and very difficult and damaging to his hair (also expensive). Does anyone have any information on this?

Yes, it will require a several-step process.

Hairdressers seem to prefer Effasol (basically a bleach) to strip the color. Effasol is a glorified bleach. I'd recommend ColorFix (a reducing agent). Colorfix will "reduce" (that doesn't mean "shrink" -- it's a chemical term -- it's the opposite of "oxidize) the color molecules. In their reduced state, they can be washed out. This isn't as simple as it sounds, however. You'll need more than one application of ColorFix to get the black out. There are other color removers (as opposed to color strippers) also (ColorZap, Color Oops, Igora Phantom and Igora Modulat)

Here are instructions for using ColorFix:

Hair Color and Hair Care by Robert Craig Salon Products, Ltd.

After getting most of the black out, you'll still have to bleach out some of the black, I suspect -- and then tone.

Since it's been 3 months, he should have an inch and a half of new growth. I assume he needs more length or you'd simply cut off the black.