friend needs love advice?

A friend of mine needs some advice but I dont know how to help her cause I have never been in her situation... She met a someone she really clicked with really fast and he seems really into her ...sometimes. It pisses her off because he comes in and out of her life wanting to see her then just blowing her off.. She decided a few months ago that she wasnt gonna give in anymore but decides to call him out of the blue only to hear him and another girl having sex (we guess that he meant to hang up but his bluetooth picked up) . Well she lets him know what she heard then avoids his calls texts and messages. Then she gives in (but not enough to see him). So then he blows her off again. So they didnt hear from each other for about a month until recently he has been texting her'when are we gonna make love again'she answers'when you are done with all those chicks'he replies'I will be done when we can kick it again'. She asked me what 2 do but I dunno what the hell to say.