My 68 yr old dad is having multiple (5-8/24 hrs) short lived (10 min) episodes of one sided paralysis. Its not tia, what else can it be?

Focal seizure/TIA. Transient 1 side weakness is either focal seizure or (less likely) tia. An eeg and brain mri/mra may pinpoint the exact area in the brain cauing these symptoms. A neurologist is the best doctor to sort out the diagnosis and recommend treatment hope he is better soon.
Seizures? If strokes/tias have been excluded, it is worth looking at other causes - seizures, damage to spinal cord (unless face is involved, then it is unlikely), migraine, anxiety/stress-related.