Hi, Welcome to JustAnswer. I'm a licensed veterinarian and I'll be happy to help. This sounds the most like he is having seizures. For how long, and how often is he having these episodes?
Thanks for your reply. Sounds much more like a seizure. Your dog is the normal age for epilepsy to begin. . .2-4 years, and this is likely what is happening.
Your vet should check him for other organ disease with a blood profile and a urinalysis just to make sure that he is not having liver problems, kidney problems or blood sugar problems, and if all is OK, will discuss with you placing your dog on anticonvulsants.
You are very welcome. Hope you have wonderful holidays. . .I'd love to visit Ireland!!!!