Beneficiary can not go on with policy.. WHY???

My parents had a policy with NHB for more than 25 years. My dad passed away in January. Now the policy is cancelled. I asked but why my mother is still alive and she was a beneficiary why is it not possible that she can carry on with the policy. Well after how many emails the answer was just no she can not carry on with the policy. She also can not take out a new one because she is 72 years old now. Why is the policy cancelled when the main member passed away.. This is ridiculous. Now on her age I am struggling to get her on a funeral policy because of her age. This is unacceptable.