Apparently there is a segment of the population in America that says the word "whenever" in place of "when." WHY?

For example: "do you think your mom's gonna be doing that whenever [child's name redacted] gets here?"

It's not some theoretical child that they will one day have- this child has an approximate time of arrival, so why would they use "whenever"? This does not make sense to me. Does anyone out there understand this usage of the word? I've never heard of people using "whenever" in place if "when" until I started watching this show. PLEASE HELP ME I WANT TO UNDERSTAND!!!