Wow, so much going on there. Hugs to you and your family You must be a very strong woman to hold all of this together Missy. Is there any chance Dad will help with $$ I assume DCFS is child services? If the abuse ended that long ago, can you really call what the older brother did as abuse? The teen abuser made them do things together... the older one just coninued to act this out after the teen moved on, but if it ended 7-10 years ago, then it stopped before the older one even reached puberty. Is this still considered abuse? Is the child services a venue that can be used to get you son therapy that would be covered somehow?
About blaming yourself, this happened when your boys were away from you with their father and combined with mental illness issues, I think it is very fair to have missed some signs if any existed. My H (abused 6-12 yo) is an absolute master at hiding any signs of his abuse. No one had a clue when he was young and no one knew until his younger brother (also abused) told the family. My H appears grounded, easy going and confident. He spent many years being the hockey star and then a singer in a band, that no one saw the real him... just this facade that he wanted everyone to see.
Let your blame go... it will only sap your energy from being able to deal with, make sound decisions and support your sons now. I wish you all the best and wish I could have given more concrete advice about your situation now.
I am not your rolling wheels, I am the highway
I am not your carpet ride, I am the sky