I have a female friend from Mexico that has been a Muslim for 3 months.
She has been married for 25 years now, has a nice family, and a nice Christian husband. He lets her believe what she wants he believes in freedom of belief. She loves him so and loves her family. She wants to know: should she divorce her husband of 25 years now? Please answer to me quickly because she does not know what to do. All information that I gave for you is right because I know her family and her husband. They are so nice and never ask her about her belief; they let her be free and respect her so.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

If a woman embraces Islam before her husband and the husband remains on his disbelief (without embracing Islam) then the wedlock becomes invalid. Therefore, she is obliged to observe a waiting period. If he embraces Islam during her waiting period, then he can take her back as his wife. The evidence for this permission is that “‘Ateeqah daughter of Al-Waleed ibn Al-Mugheerah embraced Islam nearly a month before her husband and then he embraced Islam. The Prophet approved them on their marriage ”. [Malik].

Ibn Abdul Barr said: ‘The reputation of this Hadeeth is stronger than its chain’.

Therefore, your friend should wait for three periods, if she still menstruates; otherwise she should wait for three months or till giving birth if she is pregnant.

If her husband embraces Islam during her waiting period then the marriage will be still valid; otherwise, the marriage will become null and they become forbidden for each other. A Christian or any other non-Muslim cannot be a husband of a Muslim woman. There are many supporting proofs for this ruling. The following verse is sufficient: {… And do not marry polytheistic men [to your women] until they believe. And a believing slave is better than a polytheist, even though he might please you. …} [Quran 2:221].

Allaah Knows best.