It sounds like your husband does not meet the residency requirements for his Canadian PR for no other reason than choosing to live in the US rather than in Canada.
If that is the case, he could try to move to Canada but if they catch him, they will report him and revoke his PR. If they don't catch him, he'll have to stay 2 years straight without leaving in order to meet the residency requirements again and during that time, he can't sponsor you and the kids.
Another option would be to renounce his PR status and apply for Canadian immigration from scratch if he qualifies under the current immigration programs. Then he could apply for PR for all of you at the same time.