That shouldn't really be necessary if his bicycle is set up correctly and he has the right saddle. He has also been doing quite a bit of cycling so it isn't like he's new to it.

It's a rare day when I break out any creams. However, I bring Ozonol with me, and may use a tiny dab of it on particularly hot or wet days which will cause my sitting area to be wet for an extended period of time (and thus may cause a rash), but other than that, I don't use anything. Plus Ozonol has the additional benefit of being anti-bacterial so it can also be used on road rash and other cuts and scrapes.