回复：我能否带我儿子去边境延期呢？

I don't know this situation. But you may be interested in the following information.

When I came to Canada with my kids (they have US passports) for the first fime to get my work permit, the period of legal stay of my kids in Canada was the same as the period of my work permit - 2 years. We passed the Canadian border several times by air since then. Every time my kids got the same period of stay as my work permit even though they are officially visitors without Canadian visa.