Elfies I can understand how devastating your mum's comment must have been and I'm so sorry this continues to upset you.
I don't know what to say, other than that some people hit out at others when they are afraid and in pain or discomfort. Also, sometimes when people are very ill it affects the brain and their thinking processes.
I hope that your relationship with your husband and children recovered and is of some comfort to you. It is quite common for adult children of hyper-critical parents to make great efforts to win their love and approval and you should not blame yourself for the way you responded during your mother's illness.
I wish you well and hope you can now allow yourself to be happy.
A new definition of what constitutes British

but it sounds as if that would be no bad thing
(Tin hat time for me maybe)