I concur in much of what has been posted.
I am further responding, however, because the unique situation may make a big difference in the odds of winning an appeal of a PoE issued 44(1) Report and Departure Order.
First:
During the visa processing, lo and behold, we discovered that my mother is still deemed a PR of Canada.
In addition to the original landing document, if it was a communication from IRCC which alerted you that she is still deemed a PR of Canada, a copy of that in hand as she arrives at a PoE should help verifying she is a PR, still a PR, and also illuminate the circumstances of her return to Canada.
Of course to do this she will need status to travel to the U.S. And then travel to a land border crossing.
But I agree with others that the odds of being granted a PR Travel Document are very poor, and the odds of winning an appeal of that are also very poor. Probably not much chance of even getting a special PR TD to travel to Canada pending the appeal.
Better odds of successful appeal once in Canada:
In contrast, while it is very difficult if not impossible to reliably forecast the outcome of an appeal for a border-issued 44(1) Report, the odds of succeeding in such an appeal go up considerably if in the meantime she is in Canada and it would impose a significant hardship on her if she is required to leave Canada and return to her home country. The IAD hearing is in effect de novo. While the days in Canada since arriving at the PoE, and being issued the Report, do not count in the calculation of time in Canada, all the other circumstances attendant her life since arriving in Canada do count in the assessment of H&C reasons.
Most PR RO H&C cases are based on explaining reasons for not returning to Canada sooner (and she should indeed make the case that it was her spouse's decision which compelled her to leave and not return to Canada sooner). But prospective hardships attendant having to leave Canada can be very important reasons why a PR should be allowed to retain PR status. For a person currently abroad (such as a PR applying for a PR TD), that in itself tends to show it is not an excessive hardship for that person to lose status to live in Canada. But, once she is in Canada, and has been in Canada six or ten months, preferably longer, waiting for an appeal hearing, the IAD would have to weigh how much hardship it will be to send her to Pakistan. If her primary family is now in Canada, that could tip the scales.
A lawyer's help would be a very good idea. As I have oft noted, all H&C cases tend to be tricky, at best. The length of absence in this situation weighs very heavily against allowing the individual to keep PR status. But it seems to me this is nonetheless a situation in which a well-crafted and prosecuted case should have a decent chance of success.
And contrary to what some say, even if she loses the appeal and loses PR status, that does not necessarily mean she must then leave Canada. While I am not well-acquainted with the process and procedures involved in contesting deportation, there are definitely some avenues for seeking either alternative status in Canada or for relief from a Removal Order. In particular, I believe she would be able to make a separate H&C case for being allowed to stay in Canada. This is another reason why it would be important to have a lawyer's assistance and to be prepared to pursue other recourse in the event the appeal is denied. I am not sure, but my sense is that given the differences in what constitutes sufficient H&C grounds to allow retaining PR status versus H&C grounds in other contexts, especially as to challenging physical deportation, even if the H&C case to retain PR status fails, there may be a sufficient H&C case to avoid physical deportation.
However, all this is dependent on her being able to travel via the U.S. so she can arrive at a Canadian PoE at a land crossing.
