My Mother Was In Hospital For Just Over A Week

My mother was in hospital for just over a week being treated for severe dehydration caused by a flu type bug that gave her vomiting and diarrhoea. She is 89.5 yrs old. When she was admitted via A&E they first thought she had sufferered a stroke but after I explained what happened they realised it was because of very low sodium levels. Anyway, they treated her with glucose and sodium drips and Keppra drips into her arm.
She is now out of hospital recovering at home. She has been told to take a 500mg tablet of Keppra twice a day, for six months; but she thinks these are not agreeing with her. Is she safe to stop taking these now that her sodium levels are now back to normal?