She wouldn't have had to do anything. According to the "family," HCSO's stance is this is a "missing person" case, not a "death investigation," "homicide investigation," or a "suicide."
If Mrs. Chambers knows otherwise, she hasn't said.
Our VI also said a DROP distribution election form -the document at the link, I believe- had not been mailed in by the deadline, and that Mrs. Chambers feared payments would go from month-to-month to every six months, but as posted earlier, we found out that for the payments to go semi-annual, The Chambers would have had to return the form by Feb. 28th - 10 days before Mr. Chambers went missing.
So their monthly regular pension payments would have continued just as in the past if she hadn't done anything.
Though unlikely, IMO, if Mr. and Mrs. Chambers were having paper checks mailed, rather than having pension payments direct-deposited, then Mrs. Chambers could have filed "a sworn petition stating the facts that make it desirable for the petitioning spouse to manage, control, and dispose of community property described or defined in the petition ..." under the Texas Family Code. This action might have enabled her to complete any DROP-related paperwork needed to keep those payments going as well. I'm just not sure about their DROP situation since what our VI apparently has been told does not jibe with published information.
https://www.dpfp.org/images/PDFs/Forms/Rollover-with-waiver-and-notice.pdf
His distributions don't start until he turns 70 1/2 - in May