If it was not caused by a brain tumor then that would be another possibility. If you'd like to read up on epilepsy in dogs this site really covers lots of things from causes to medications etc.
http://www.canine-epilepsy-guardian-angels.com/site_map.htm
If you still know your dog's breeder it might be worth telling them. They might know if other dogs in the litter had similar problems.
Keeshonds usually live to be 12 – 14 years on average and as with any average some will be below that and some above.
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