The whole family emigrated and remarried.

If your son gets married, he will be an independent individual, because he has his own family, so if his parents want to go there, they will be family reunion immigrants. As for marital status, it is necessary to submit some relevant certificates, such as the divorce agreement with the former spouse and the marriage certificate of the current spouse. You also need to submit a statement from your ex-spouse (that is, a statement that you will not accompany you to Canada and will not object to your immigration to Canada). The specific information submitted is available in official website, Canada, and will not affect your immigration. The main concern of the immigration officer is what your divorced ex-spouse thinks of your emigration to Canada and whether you can survive after emigration to Canada. They don't care about your marriage and divorce, as long as there are corresponding certificates to prove your marital status.