[fbkeays]

If your friend is concerned about doing the spay before the first heat to lessen the chance of mammary cancer, he can relax a bit. Yes, going through one or more heat cycle does increase the risk. But put things in prespective.
First off mammary cancer is a lot less prevalent then bone cancer. Staying intact will REDUCE the risk of bone cancer and many other FATAL cancers. Mammary cancer is rarely fatal, while bone cancer is always 100% fatal. Your friend just needs to be watchful of any of the signs of mammary cancer and pyrometra (which typically happens about 2 months after a heat cycle). It is an infection of the uterus and if caught early, can be treated with drugs.
While spaying does prevent mammary cancer and pyrometra, it opens the door to a whole host of very nasty and deadly cancers that are much worse IMO. If your friend is an attentive and responsible owner, staying intact is not a bad option.