First, they can pay 'out of pocket' for sex therapy. They can also visit cancer organizations' web sites, like the Association of Cancer Online Resources , and join an e-mail support group. These list servers are private. There is no way for anyone outside the group to get your e-mail address. Your questions can be posted and other people anywhere in the country or world who have dealt with a similar concern may share how they have handled that problem.
Counseling is excellent if people can afford it.
If they can't afford it, then education and support are very helpful. Certainly get educated because isolation and stigma are probably the biggest enemies of healthy sexual function. The most common sexual difficulty is fatigue. Fatigue will drive sexual desire into the ground. When people are going through any kind of chemotherapy or radiation or following surgery, they need to be flexible.