What if son-in-law does not include daughter's name in green card form

I am assuming that your son-in-law is pursing employment-based green card. If your son-in-law does not include your daughter's name on the Form I-140, Immigrant Petition for Alien Worker, she will not able to get her green card either through adjustment of status in the United States or through Consular Processing at the U.S. Consulate in India. It is critical that her name gets listed on the Form I-140.

If your daughter returns to India, she may be allowed to travel back to the United States using her L-2 valid visa till the time she remains married to your current son-in-law. If her visa has expired, she would need to obtain a dependent visa (L-2) in order to travel back to the United States. It is a must that she remains married in order to obtain the L-2 visa and should have proof that her husband is currently maintaining valid L nonimmigrant status in the United States.

The situation might change if your daughter finds an employer in the United States who can sponsor her for an H-1B visa. If that happens, she can have her own H-1B visa and she will no longer be on a dependent visa like L-2.

I hope this helps.