My goal here is it be as informed as possible about my friend’s options. Note that she is going to see and has already seen a Lawyer.
Her ex-husband lives in New Mexico. They divorced in Mississippi 15 years ago. She lives in Louisiana and has done so with their three children for 12 years. She has had physical custody of all three children for those 12 years. Also note the children have never lived with him and that he has been 100% absentee for those 12 years.

Two months ago she sent her middle son to live with her ex-husband. She received an email from his attorney showing motions being sent to New Mexico courts requesting that jurisdiction of the divorce decree be moved from Mississippi to New Mexico. Note that she has NOT been served yet. Also, they are requesting she signs and notarize a form waiving her needing to be served.

Questions:
1. Under UCCJEA; the Mississippi courts will most likely relinquish jurisdiction during initial determination as it is no longer the “home state” of the children. Also there is no parent that has a significant connection with Mississippi anymore, and evidence concerning the child's custody determination is not available in Mississippi as they have lived in Louisiana for 12 years. How does Louisiana become involved in this determination?
2. Will the New Mexico court during this determination reach out to the Louisiana court system?
3. The motion from his attorney to the New Mexico court stated that:

“The Petitioner resides in New Mexico and has so resided for six months prior to filing this Petition.”

“The child no longer resides in Mississippi and now resides with the Petitioner in New Mexico.”

“Mississippi is no longer the home state of the minor child and New Mexico now has jurisdiction over (minor child).”

“The Respondent no longer has residency or significant contacts in Mississippi, therefore jurisdiction is no longer property and the forum is no longer convenient for the litigation of the parties’ interests.”

“New Mexico has jurisdiction to register the aforementioned out of state decree; in that the state of original jurisdiction no longer has a claim to jurisdiction by virtue of neither parent nor any minor children continue to reside there.”

4. The attorney made no mention of her and the minor children having lived in Louisiana for the last 12 years. Will the New Mexico court prior to seizing the jurisdiction reach out to the Louisiana court system to see if it merits the jurisdiction?
5. How does Louisiana get involved in this determination? I know all three states follow UCCJEA.
6. Is it beholden on New Mexico court to involve Louisiana? Or will the New Mexico court system just take what the attorney motioned above and once Mississippi relinquishes jurisdiction; take it.
7. While she is getting a Lawyer; would their next step be to file a motion in the Louisiana court system? So that the Louisiana court will become involved in this determination?
8. The first Lawyer she met told her to reach out to a New Mexico attorney as they understand the New Mexico court system. Also to have them file an objection to the above motion. Is this the better option?

What other options does she have? How can she make sure the jurisdiction falls to Louisiana where the child has resided for 12 years? Also where her other two children still reside.

9. Lastly; what happens once the minor child has been in New Mexico for 6 months? How time sensitive is this matter? He has been there for two months now.

Thanks for all your responses!