As long as its not major he can simply move the fan up a little bit on the cooler, I had to do that with my RAM. Or he can move the fan to the rear and pull air through, or buy one of the thin fans.Depending on the model of your ram, in the worst case, you may have to remove the front fan entirely.
Naked ram has a height of 31mm. The NH-D15's front fan will sit comfortably on top of the first stick.
Using memory with heatspreaders will force the front fan to be raised for each millimeter over the standard.
@richiestang_78
Too soon to say that without considering what the OP's ram might be.