Uni policies can vary, so there's no way we could offer anything other than a guess about what they'll do. They won't necessarily be guided by the final police action, as he was given a police caution and clearly did it. There's a standard concept in uni regs of "bringing the university into disrepute", which could (worst case scenario) result in the uni throwing him out. Most universities would want to be seen to be protecting female students against this kind of harrassment. Even if he gets off lightly in the immediate future, it will go onto his uni record and might affect future job references. Wouldn't want to be him right now, frankly.
He should consult his Student Union if he thinks he might need help, but he should prepare for them to not be particularly sympathetic.