Avuncular people are those having traits considered typical of uncles; jolly, indulgent, stodgy, etc. or: resembling an uncle; friendly; helpful. I find this preconception of uncles curious but having had only one uncle in my life my sample is not representative. Then again, as my faithful Merriam-Webster's writes:
„Not all uncles are likeable fellows (Hamlet's murderous Uncle Claudius, for example, isn't exactly Mr. Nice Guy in Shakespeare's tragedy), but "avuncular" reveals that, as a group, uncles are generally seen as affable and benevolent, if at times a bit patronizing. Avuncular derives from the Latin noun avunculus, which translates as "maternal uncle," [and is itself a diminutive of avus, grandfather, though Merriam-Webster's does not care about that] but since at least the 1830s English speakers have used "avuncular" to refer to uncles from either side of the family or even to individuals who are simply uncle-like in character or behavior. And in case you were wondering, "avunculus" is also an ancestor of the word uncle itself.“
That seems to imply that to be avuncular is a nice thing to be or to be considered to be, but the idea can only to be applied to men. German has the very similar concept of onkelhaft for an uncle-like behaviour. It even has the tantenhaft for an aunt-like behaviour (that one is not so nice, as it is often translated as old-maidish: language sucks and is not politically correct).
But in Spanish I am at a loss to translate either word: avuncular, being of Latin origin, should be easy. Well it is not. Either Spanish uncles are not so nice as English and German ones or Spanish nephews do not notice.