I think my dad attempted suicide?

My dad is currently being hospitalized for carbon monoxide poisoning. I found him today, at 6am, past out on the living room floor claiming to not be able to move when we got him up. We called the ambulance and it took him to the hospital. My dad has been a mechanic for 30 years so he knows about having a running vehicle in a garage, without any ventilation, is death waiting to happen. Yet the doctor says it is of carbon monoxide poisoning. He also hasn't eaten in 3 weeks, hasn't slept in 3 days, and has had chess pains for about 4 days. He doesn't drink alcohol or do any drugs. What caused him to be wasted like how I found him? The lack of sleep or the lack of food? Did he have a stroke? Plus, why would he have wanted to die? He has his dream job, does what he loves, has a family that loves him, etc.? He has never been diagnosed with depression but does get fairly depressed every so often. He hasn't been diagnosed with Autism though I have it as well as OCD and Depression. What hapend