Sometimes people do nasty things, and sometimes this results in betrayal. Reacting with outrage won't fix the situation. It is better for you, both now and in the long run, to remain calm and focus on practical matters. Don't ignore the situation, but go about your daily life without obsessing over the outrageous behavior.
Friends joke with one another. Hey, you're poor. Hey, your momma's dead. That's what friends.. (read more)