I live in the Phoenix area. With 112 F as the ambient temperature, the interior temperature of a car skyrockets immediately after you turn the AC off. The car becomes noticeably, dangerously hot very quickly.
Four kids is not too many to keep track of. I don’t know how a mother could possibly forget about her baby under the circumstances. My theory: she was impaired from drugs, alcohol, both.
By all means, never give anyone the benefit of the doubt.
Someday you’ll have the favor returned.