Ok, thanks everyone, I've got the plan.

In the case that their flight is even remotely on-time:
-on-line check-in before they leave
-Convince them to either not check or plan to abandon the checked bag by 1 hour prior to connecting flight
-convince them that people without checked bag should not wait, just go to gate asap
-if they miss, go to AC service desk and beg to get on another flight, for maybe just the change fee. They will have to overnight somewhere.

In the case that their flight is delayed and they are obviously going to misconnect:
- I will contact AE on their behalf and try to get them rescheduled while they are still on their sunwing flight. At least as an SE i don't have to wait in the phone queue forever.