Sorry to hear your young dog has suffered a stroke. Many years ago I had a Golden Retriever who suffered a stroke at around 11 years of age. With plenty of rest he started to use his legs again and although he tended to walk a bit 'crablike' for a short while, he did eventually manage to straighten up and lead an active life until at 16 he suffered another one so I thought it far kinder to have him PTS.