An Absent-minded Dad

I didn't think something like this could happen in real life.

baby found dead in a car

Could the dad be under the influence of drugs that he would just "forget" about his baby? Could he be sick with alzheimer's? Or could he simply be out of his mind?

My sympathy goes to the baby's mom. A 4-month-old is just too tiny and fragile to be exposed to anything or anyone that could bring her harm, even if it means her own daddy.