Hello there....I can understand your concern. It is difficult to tell if your friend will get
hiv infection. It will depend on whether the girl he had sexual contact with has hiv infection. If she has hiv, then there's a high chance on him also getting it, especially if it was unprotected sex. However if he used a condom, then the chance of transmission is minimal. For safety let him get a hiv 1 and 2 done now and repeat after 6 weeks. And ask him to follow safe sexual practice.