i did a lot of reading about this after two of my friends got HIV. during intercourse, many tiny cuts can occur in the vagina - the rougher the sex, or the longer it lasts, the more tiny cuts. this is not abnormal, but it is an excellent way to introduce HIV from the semen to the woman's bloodstream.
http://my.webmd.com/content/article/85/98749.htm
"Information gathered through the AIDS Public Information Data Set and HIV/AIDS Surveillance Reports estimates that at least 54 percent of all AIDS cases in women came through heterosexual contact with a person not known to be infected or of high risk."
it's very sad that your friend's boyfriend is willing to let her risk fucking DEATH because he doesn't want to use a condom. what a jerk!