Is the waiting period (iddah) obligatory for the mother, and is it obligatory to inform her of the father's death, given the fear of her health deteriorating?

A woman whose husband has passed away is obligated to observe 'iddah (mourning period) for four months and ten days, based on the Almighty's saying: (And those of you who die and leave wives behind them, they (their wives) shall wait (as regards their marriage) for four months and ten days). And based on the Prophet's (peace be upon him) saying: (It is not permissible for a woman who believes in Allah and the Last Day to mourn for a deceased person for more than three days, except for her husband, for whom she should mourn for four months and ten days).

'Iddah entails: refraining from adornment and perfume, and not leaving the house during the day except for a necessity, nor at night except for an emergency. However, if the woman observing 'iddah does not comprehend the rulings of 'iddah or if there is a fear of her reaction upon knowing the news, then she should not be informed. Her guardian is then responsible for preventing her from what is prohibited for a woman observing 'iddah.