I understand you are getting at but it would not be a good look for OP if she communicated with him to jeer at him that he has a tiny dick and then reported his offence to the police. It would make it look - to the police - like OP and friend's H have a relationship of some sort, it would completely muddy the waters and it might mean the police don't take it seriously.
Also, with regard to "We're not dealing with someone rational here". That sounds very much like "he must have taken temporary leave of his senses, the poor man, once he sobers up he'll be back to being a solid rational bloke."
This is an excuse that lets this man off the hook for feeling entitled to sexually harass a woman in her own home. Women are increasingly refusing to accept such excuses because this kind of intrusive aggressive shit behaviour is an epidemic that causes women to feel unsafe in the street, at work, in gyms, and in their OWN HOME. This man is as rational as all the millions of other men who send unsolicited dick pics to women. These men do it because it pleases them and up until now, the vast majority of them have gotten away with it. They don't care about the women who they send the pic to, they don't care that she could feel shocked, assaulted, and threatened by it. They also don't care if she tells them they've upset her - most laugh, feel validated, and are even turned on by the attention. Men like this don't see women as humans, they are just passive objects and receptacles of their lust.
This kind of mentality needs to end, and it starts with not excusing the behaviour of these men.