My aunt (from dad side)'s daughter&my little brother both have had history with seizures. Is it hereditary? Are my future children at risk for epilepsy?

Consult neurologist. There are many reasons for seizures to manifest in children .Some of them may be hereditary .There are different type of seizures ,some hereditary others are not .These two children may or may not be getting same type .Consult neurologist about these children ,he can examine and explain about the risk of epilepsy in your children .