Is it permissible for a woman observing the 'iddah (waiting period) after her husband's death to travel to visit her sick father in the hospital, and is this considered among the necessities that permit her travel and leaving her home?

A woman whose husband has passed away must observe a mourning period (iddah) of four months and ten days, or until she gives birth if she is pregnant. It is a condition that she does not spend the night outside her home except in case of necessity. She is permitted to go out during the day to attend to her needs. If visiting her father requires spending the night outside her home, then it is not permissible, unless the visit does not necessitate spending the night and she can return to her home; in which case, it is permissible if there is no fear of temptation, bearing in mind that some jurists have absolutely prohibited the travel of a woman in her iddah.