How To Prove No Divorce?

Location: Texas, USA I have a family member who was separated from her husband at the time of his death in 2024. He was in a care home where his daughter worked who was estranged from her stepmom and who blocked her efforts in contacting her husband. When he passed, the daughter reported to the funeral home that he was divorced, so that is what was listed on his death certificate. His widow is trying to access benefits she is entitled to, but is now unable to because she is not listed as his surviving spouse. Texas Department of Vital Records told the widow that she needs a court order saying there was no divorce (which a lawyer told her would cost $6K minimum since there was no will). Life insurance is now asking for an amended death certificate or divorce decree (even though she is listed as his beneficiary as far as we know), neither of which she is able to provide. She also cannot access her husband’s pension or SS benefits.
To make things more complicated, the couple was married in the early 90s, divorced a few years later, but then reconciled and remarried. So there is an existing divorce between them, but with a marriage after the fact. The widow no longer lives in TX and is hoping to get things resolved without having to go to court. Does anyone know how she can get the death certificate amended (without too many expenses or hopefully without getting a court involved)? Her late husband lived in Texas his whole life, so any vital records should have been in their system. And if she does have to go to court/get a lawyer, any advice on the process would be appreciated as well. Money is tight but might not qualify for income based assistance.