No matter the supervisor or the objective factors, the author need not worry too much. What the author needs to do is to explain the main reasons for overdue to the magazine, and pay attention to the sincere tone. Most magazines won't be difficult for authors at this point, and most will understand the problem of overdue. However, there is a premise that the overdue time should not be too long, and it will not be easy if it is too long.
In principle, if the revised sci paper exceeds the deadline, it is equivalent to rejection. If the author writes to the editor in time to explain the reasonable reasons for the extension, it is generally ok. That is, the revised sci submitted after the deadline is also accepted and will not be rejected directly because of the extension.