Carbon Monoxide Scenario

You are working with a Technician on an EA, it is the afternoon of a busy day shift, and you receive a call to a dizzy/unwell male. You promptly arrive on scene where the door is ajar. You grab your kit and enter the property. As you enter, you call out and a reply comes from the front living room. Sat on the sofa is a male patient in his sixties. He explains that he has been feeling unwell in the house over the past couple of weeks with dizziness, lethargy, and nausea. Today he felt he couldn’t walk properly and felt unwell. He was wondering if he may have had a stroke as he just can’t concentrate on things properly.