It would indicate to me that she had very low self esteem and was so needy and desperate, she wouldn't mind going back to a very cruel person. And he'll probably think he has an opening to get laid and she'll let herself be ghosted again. And he's probably right.
If this is you, don't do it! Nothing good will come of it.
Difficult to say. And probably for every guy different. If I ghost woman then there is a really good reason. Most likely being a female version an asshole. It is safe to say that if she contacted me she would still be Casper to me.
Another thing is if I needed some distant from her (or some reason). But most likely I would have told her from the beginning that I am cool but just need some distance. If she contacted before I am ready I would be polite but tell her I still need some distance.
If we somehow lost contact and she contacted me after a long time I would be genuinely completely nice to her. I see no reasons to not be.