Translation:Even grandmother is coming to visit.
Some expressions are like that, a lot of words in one language and one short one in another, maybe not even remotely of the same origin. And while I'm at it, Farmor is strictly speaking not just a grandmother, she is the paternal grandmother (mother of the father). The maternal grandmother is mormor (mother mother...). The generic grandmother is bestemor (best mother).
Til og med ~ to and with, if you were to translate it word by word but that makes no sense at all. Even translates to "Til og med" in a standalone phrase. Not even grandmother... = Ikke engang bestemor. In mathematics even = partall.
Partall is even number (par and tall); I do not know whether it applies to even functions and other even concepts. https://ordbok.uib.no/perl/ordbok.cgi?OPP=partall&ant_bokmaal=5&ant_nynorsk=5&begge=+&ordbok=begge
Farmor is a term that doesn't have a clear equivalent in English, both your parent's mothers will both be a grandmother (the generic which in Norwegian is bestemor). So then we have to allow for all different forms of grandmother that exist (gran, granny, nan etc), and of course the literal father's mother and paternal grandmother. "Grand" is not on that list as far as I could tell.