By "do something he doesn't believe in," you mean support women's right to choose?

No one is forcing anyone to support a woman's right to choose, even if they should (because gestation and childbirth are potentially harmful/fatal and should be entered into willingly and by an informed individual).

What he gets out of it or doesn't get out of it should be irrelevant, if he's capable of looking beyond his personal needs and desires. Many people aren't.