New Mexico statutes require that the lien claimant file a lawsuit to perfect the lien within two years of filing the lien.
See 48-2-10 at:
And 48-2-9 at the same link addresses petitioning the court for an order cancelling the lien.
I did a quick internet search but could not find a sample petition so you will have to figure out how to do it yourself or get some legal help.
I did come across a list of cases in Bernalilo County District Court that included one case where someone included a petition to cancel lien:
Express Investments Inc. v. HD Supply Inc. Voluntary dismissal (complaint for quiet title, for damages and punitive damages, for slander of title, and petition to cancel lien).
If you are in or near Bernalilo County you can visit the courthouse, examine the case file and get a copy of the petition and use the format for your local court and change the wording around to suit your mother's situation.
If that doesn't work out for her, she might be able to get some free or low cost legal help from one of the following resources: