My grandma has hypertension and kindey disease stage 4 17%. she had a sudden brain stroke around 5.45am and caused severe bleed in the brain. can this be solely caused by she probably missed her one dose of hypertension medications or other factors?

No, it's not. Most blood pressure medications have long acting effect so missing or skipping one dose rarely causes a significant spike in BP. Your grandma has HTN and almost end stage CKD so she is at very high risk for stroke due to widespread atherosclerotic vascular disease. She likely has cerebral bleeding post ischemic stroke. Missing one dose of anti-hypertensive med is not the culprit.

I don't think we can say for sure what caused the hemorrhagic stroke, but hypertension and chronic kidney disease are 2 conditions, especially in elderly patients, that make one prone to intracerebral hemorrhage.