What Causes Dizzy Spells Along With Slurred Speech And Headaches?

My husband became dizzy, had slurred speech, headache and nausea after he was using paint thinner in the basement, although the small windows were open. It s been two hours since then and his speech was no longer slurred and he has fallen asleep saying he still had a bad headache and nausea. He didn t even want water. He had not eaten anything except for a couple of cups of coffee in the morning. Should I let him sleep and/or give him some food or liquid? Should I take him to an emergency room?