assalam alaykum ... I just got married again and Allah blessed me with two little kids Alhandulillah and my husband was married to a Christian women in American way and he had a son with that women. The son is Christian he is 16 years of age . what should i do when he come to see his dad

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

A step-son is one of the Mahaarim (plural of Mahram) of the woman. The fact that he is a Christian does not prevent this. However, if you notice a suspicious behavior from him, then you must treat him as non-Mahram.

Some scholars are of the view that it is forbidden for a woman to travel alone with a non-Muslim Mahram; the scholars of the Hanbali School of jurisprudence stated this. Ar-Ruhaybaani from the Hanbali School of jurisprudence said in his book Mataalib Ulin-Nuha: "Note: A Muslim woman is not allowed to travel with her non-Muslim father, because he is not a Mahram to her in travel, although he is ruled (and considered) to be a Mahram; this was explicitly stated by Imam Ahmad." [End of quote]

We recommend that you take care of this child, teach him Islam and encourage him to embrace it by your good treatment and so forth. In this regard, you can benefit from the following Fataawa on our site: 8210, 10326 and 90449.

Finally, it should be noted that this is one of the serious effects of a Muslim man marrying a woman of the People of the Book. Due to the risks and dangers of such marriages, some scholars disliked it, although it is in principle permissible. The Fiqh Encyclopedia reads:

"Although it is lawful for the Muslim man to marry a woman from the People of the Book, some scholars held that it is disliked because it is feared that he might become too attached to her to the extent that she might tempt him and, thus, drive him away from his religion or that he would become an ally to the people of her religion. ʻUmar ibn Al-Khattaab said to the Companions who married women from the People of the Book, 'Divorce them!' Imam Maalik was one of the scholars who held that it is disliked marrying a woman from the People of the Book because she nourishes on wine and pork and feeds them to his child (through breastfeeding). He (the husband) kisses her and engages in foreplay with her while he is not entitled to forbid her from wine and pork, even if he is harmed by the bad smell (of wine or pork) during their intimate time together. Also, he cannot forbid her from going to church, and she may die whilst pregnant with his child and would then be buried in a non-Muslim cemetery where her grave will be a pit of Hell, and the child, who is part of his Muslim father, would be inside her womb in that pit..." [End of quote]

Allah knows best.