I feel like making my grandmother cry.
Why would you want to make your grandma cry?
She is taking medicine and is weak. I want her to suffer.
That is horrible. You shouldn't make your grandma cry. She is clearly suffering.
Believe it or not, I won't feel bad.
Regardless of how it makes you feel, if you make your grandmother cry then she may not want to be around you anymore. You may damage your relationship with her and other members of your family. If you can't stop yourself from mistreating your grandmother, then just stay away from her.