Final answer:
The mother is most likely experiencing the stage of denial according to Kübler-Ross's five-stage model of grief.
Step-by-step explanation:
The mother is most likely experiencing the stage of denial according to Kübler-Ross's five-stage model of grief. Denial is characterized by not wanting to believe that one is dying, and common thoughts such as 'I feel fine' or 'This is not really happening to me'. Anger, bargaining, depression, and acceptance are the subsequent stages in the model.