Yesterday, my dad had headache 2/10, blurred vision,said he experienced partial memory loss for around 2 hours. today morning he had headache 6/10. now, he is doesnt have one, no blurred vision, no paresthesia,he sais he's ok, should he go to the er?

In my opinion, your dad should have gone to the ER yesterday, while he was experiencing sudden onset of neurological changes. Review with him all possible symptoms of stroke and TIA. If he has any of those symptoms again, he should be brought to his nearest ER immediately. Strokes get worse if the symptoms are ignored. There may be treatment if he is seen very early on.

Your description does raise concern on my part for a vascular insufficiency concern, and depending on age and prior co-morbidities, he needs to be evaluated for a potential transient ischemic attack, or even a small stroke. Primary cardiac issues prompting secondary neurological problems should be investigated. Contact your doctor ASAP.