In short, I'm looking for sources from anywhere that speaks about the severity of insulting an almana and all that surrounds this topic, what the "punishment" might be, what teshuva can be done, etc.
The reason I'm asking is because of the following story that took place.
An 18 yr old boy came home one Motzei Shabbos and found that his mother had invited over a woman (who is a widow - almana) and her daughter (a yesoma - "orphan".) There had been a situation previously that the daughter had been calling this boy because she thought maybe they'd get married one day (this girl unfortunately has emotional problems, depression, etc -- of course due to the unfortunate situation that her Father passed away when she was a little girl.) The boy saw the mother and daughter were in his house and pretty much told them to "get out" in a not such nice way. They immediately left feeling completely ashamed, embarrassed, broken, etc. The mother hasn't stepped foot into the house since this incident. Not having neighbors to go to has left them even more broken -- especially since these neighbors were so inviting. The daughter said she forgives him, however the Mother is still quite upset about what happened to her and as well that her daughter was insulted (since this incident the emotional problems and depression have worsen.) In any case the right thing to do now is obviously that this boy should apologize AT LEAST to the Mother. However this is not an easy thing to convince him to do.
(The tags on this question can definitely be improved upon!)