Why does one of my friends use dots at the end of his questions?

It's just something he does. He probably couldn't even tell you why he does it...

Wasn’t taught proper punctuation

Like this …

I do too...

Sometimes it's just a typo. My period and question mark are on the same key.

To indicate either a pause or etcetera, as in an ellipsis.

My old boss did 4 dots. Either 4 dots or 2 dots could mean stop. Like

This is the sentence ....

It's easier to type.

Maybe, he missed punctuation day in school.

I do the same, but mostly answers.

Why not...