A moon cycle is 28 days (the time from one full moon to the next), so a week is 1/4 of a moon cycle. However, typically the people that measured time in full moons would not talk about quarters of the moon cycle; they measure smaller periods like a week in days or nights. Up to about a "fortnight" which was fourteen days which is half a moon cycle. They might use that period, 1/2.
The ideas of "hours" and "minutes" are pretty recent inventions only a few centuries old (maybe five centuries?) In a primarily rural and non-industrial world, examine the language we used before: "morning" "afternoon" and "night" were close enough, a "moment", "quickly", "hurry", and other timely notions are very general and can mean anything from seconds to hours depending on the context of the task: "quick" milking of goats is different than "come quick."
So things like an aunt dying a week or days ago could be described as "just happened", and not specified precisely at all: To a speaker not accustomed to thinking of life events as sharply delineated in time; if they are still in the emotional grips of such a death, in their mind the death may still be an event in progress. That may be alien to those of us raised on the clock; but unclocked people (not raised on a clock) can see their lives as a sequence of (sometimes overlapping) events.
For example; "I got married" followed by "I got pregnant". How much time passed between those events may not be known for an unclocked person, because nothing of similarly memorable import happened to her in-between those events.
Had we said it, it is like her asking us "how many miles did you walk in-between those events?" We don't know, most of us don't really keep track of how many miles we walk, and it would be hard to estimate.
So our unclocked mother may be able to tell us many other events she recalls that happened in-between without an exact handle on days, weeks or months. And without understanding why we think that makes any difference.