Parents as dude...
I guess your dad could be some dude what impregnated
ur mum your mum.
Otherwise I would only expect it as an exclamation or after my (My dude, hold my beer as I show you how it's done).
On the other hand "boy" is used in some of the more rural parts I occasionally find myself in. One time I was at a car boot sale and an older guy (almost said boy myself there, maybe I should have used dude) with such an accent/dialect turned up and everybody was boy (I was, the dog was, the retired/retiring builder I was buying tools from was, said builder's grandson was) and boy was used instead of pausing between words (which tended to come very fast).
Never really considered gender lines for differing terms though. I tend to only hear it around here as a preface to a begging session (daddy, would you please buy me this), or in classic disco songs and
covers thereof.
"old man/old lady"
First a song
That gets confusing.
Someone asks me how my/the old man is doing and I will know it means my dad.
Someone's old lady is usually someone's wife/girlfriend the circles I find myself in though, and the women often refer to themselves as that (I am/was so and so's old lady). Could make for some icky misunderstandings.
Might as well have another song
I did also try to find a video covering this sort of thing and why many languages have an ma/mo/mu type word for mother, it was speculated that as it is among the first repeatable/directed sounds a baby's throat can typically make that it went from there.