I'm going to take my grandfather's cigarettes away
Why do you want to take his cigarettes away?
Hell, he smokes like a chimney and he costs us a lot of money each month
Though it's not good to smoke, it may be much too late for your grandfather. Without his cigarettes, he may go through withdrawal of some sort and be unable to handle the symptoms in his old age.
I don't care
It can be really hard for people to quit. Do you think you could get him a patch or a vape something to help fill in the gap while he quits?