I filed for back child support, have a court order, a few years ago and the attorney generals office in Texas said I can't collect. I do not understand this, he owes me.

I don't understand it either - I think I need more details.

I filed for back child support, have a court order, a few years ago and the attorney generals office in texas said i can't collect. I do not understand this, he owes me.

You asked the Texas AG to file for you, and they said you couldn't collect? What exactly did they say as the reason?

If you didn't understand them then, you should have asked for clarification from them.

Background - In 2006 the husband had had custody for 3 years (so he had custody going back to 2003) because the husband proved her (or she "let him" prove her) unfit. She was paying child support. https://www.askmehelpdesk.com/family-law/regaining-custody-29916.html

At that time - 2006, 6 years ago - she was attempting to regain custody.

I don't know how "30 year old" support now becomes an issue if it wasn't addressed then.

OR is she talking about child support HER father owes her mother that SHE is now trying to collect.

Or something else - ?

OP also has a Paralegal degree.

... OR is she talking about child support HER father owes her mother that SHE is now trying to collect.
...

You know it, and I know it, but for OP's benefit let's make it clear: OP cannot collect child support which may have been payable to OP's custodial parent. The CP payable to the custodial parent (OP's mother, perhaps?) would not be collectible by the child. The state could try, but not the child (unless the child is the executor, etc.).