Is it permissible for a mother to pray beside her son or behind him when performing congregational prayers with the family during a trip?

The Sunnah is for a woman to stand behind a man in congregational prayer. It is disliked for her to stand beside him, according to the majority of scholars, but their prayer is valid according to most scholars. Some scholars hold that the man's prayer becomes void if a woman prays beside him, and this is one of the two opinions among the Hanbalis.