My Husband Has Trouble Speaking Occasionally. He Stutters For 5-8

My husband has trouble speaking occasionally. He stutters for 5-8 seconds before a word comes out. It is getting worse. He has stabbing pains in his head occasionally and severe headaches. He doesn't take his blood pressure pills regularly. He is always hitting his head on things. He has a lot of problems with his memory. That has also gotten worse lately. What could be wrong?