Is it permissible for a husband to tear up a check he wrote for his wife without her knowledge? Is it permissible for a wife to file for divorce in non-Sharia courts to claim money and custody? What is the ruling on her family supporting her in this? What is the action that pleases Allah in this situation to protect the children?

The husband is not obligated to pay the amount written in the "check" he wrote to his wife without sufficient funds, especially in a country like Canada where this is not considered a crime. Its ruling is not affected by the fact that it is an unpossessed and non-binding gift, and it may have been given unwillingly. It is forbidden for the wife and her family to threaten to resort to infidel courts to demand divorce, child custody, or half of the property, as this is not her right. What she takes without right or willingness is not lawful for her. It is impermissible to seek judgment under man-made laws, and the wife's family should not support her in falsehood. The husband is advised to move to an Islamic environment, be gentle with his wife, mend relations with her family, and associate with righteous people to help him guide her. If cohabitation becomes impossible, he should divorce her and consider what she took without right as a charitable act (for which he will be rewarded by Allah).