tell her to schedule a tech to come pick it up, I guarantee you they will tell the CSR to go eff themselves when they hear explosion and gas line.
as to your question
Is it right for Comcast to be so insistent in this? At this time? Later?
If you let your friend borrow a weed eater, and he promised to return it, then a natural disaster hit and destroyed it, you'd expect him to replace it and if he were a friend he would already have it when he came to tell you the situation. He might be late getting it to you and you'd be expected to understand that, but you would not be expected to NOT get it back. He took responsibility for it, he owns up, that's the way it works. Right and wrong is not the terms you want to use here, legally its RIGHT.
Furthermore the person in a call center in only god knows where has no idea if your mother is an upstanding person with a real situation or a dirt bag trying to use the hurricane as an excuse to cash scrap metal to buy more meth. Its a policy, they follow it for EVERYONE, then no one can accuse them of being racists, sexist, or any other hate crime out there, that's the BOTTOM line.
That said the story is suspicious, if I were in a natural disaster I would not call comcast and I work for them nor would I bother answering their calls. If you were not food, shelter, or family your call gets voicemail, period. As someone who has lived through hurricanes, I'd be pissed you were even bothering to clog up the already stressed communication lines with this, personally.
I suppose now the story will change to she texted comcast or used the land line in her soon to blow up home, but whatever, its common sense you limit pointless communications during natural disasters so people who really need to, CAN. Like 911. And no, cable is not an emergency.