The mother may feel that she wants to hug the child in relief that he is not dying, but this can also reward a tantrum. She can give him hugs later, when he is doing approved behavior. Even though children apparently throw tantrums for desired objects and privileges, what many of them really want is their parent's attention. A hug is a form of attention. In addition, this is why spanking is not as effective as ignoring the tantrum.
Painful attention is still attention.
Painful or not, some attention is more rewarding than no attention at all. Give your children lots of hugs and attention. However, give the attention and hugs when they do approved behavior, not when they throw tantrums. In this way, you will not be teaching tantrums. Likewise, the parent involved could just as easily be the father.