My Husband Is On Keppra 1000mg Bid Due To A

my husband is on keppra 1000mg bid due to a crainoplasty per neurosurgeon. he was on the medication prior when he 1st had his stroke in 8/2016 and successfully taken off the med w/out any seizure activity. He was put back on for precautionary measures. I spoke with his primary md. who want me to titrate it off slowly. what is the least amount of keppra I can give him?