Much thinking about the Will and the paradoxes of not following it, stems from Aristotle’s discussions around it and prior to that even. The topic even has a Greek name which might help your inquiry Akrasia. Most quotable statements on the topic come, as your Dad implied, from the Classics in my experience.
I can’t identify an exact quote to the effect of the other one you mention but it sounds like a Stoic notion. Go to a scholar of that period, ask Massimo Pigliucci at CUNY-City College, he would be pleased to hear from you, or just try the Stanford Encyclopedia of Philosophy. To my mind it is likely Epicurus for a single quotable statement; his thinking, incidentally, is not very well indicated by the modern meaning of the word derived from the school he established. I will also add that in my experience and ‘research’ even, that notion arises spontaneously so to speak, quite often expressed in more or less those words. It might well have been a kind of distillation your Dad arrived at himself. The idea, as I will say in this over long reply, is very prominent in Classical Greek and Roman Thought. Bear in mind that for most of the history of this topic, human beings were and could be treated as ‘property’ or ‘possessions’.
There are really two distinct ideas round this topic, even in Ancient times; one, usually associated with the Cynics, that possessions, in themselves as it were, will corrupt and ‘possess’ you and the other idea, associated more with Stoics and Epicurus and probably steming, as your friend maybe implies, from reflection on Aristotle’s virtue theories; that intemperate attitudes towards and some consequences steming from the desire and possession of and for ‘stuff’ corrupts. The latter idea has had a lot more traction historically especially outside Christian thinking. Quotes like the one you are looking for could reasonably occur from those who hold either view I think?
I have seen the quote below several times, but nothing else closer to the Nietzsche quote you have already, bear in mind modern translations, even Greek versions, can be tricky and diverge from the original meanings quite a bit on examination. This is attributed to Epicurus and he made dozens of quotable remarks on those lines: according to his fans anyway.
“A free life cannot acquire many possessions, because this is not easy to do without servility to mobs or monarchs.” attributed to EPICURUS
Epicurus himself held roughly that it was ok to have stuff; PROVIDED you were quite happy and prepared to go back to being without them. That is almost impossible to do psychologically it has turned out? That psychological fact, if you like, that new and shiny just wears off and creates an addictive cycle of ‘retail therapy’, has come to prominence in this discussion this last couple of centuries? Bear in mind there wasn’t so much ‘stuff’ in Ancient Times, not for most folk anyway.
But I never read Epicurus as saying that possessions themselves, so to speak, were a problem. Probably why his view was so distorted by subsequent christian eras and condensed into a term for a kind of almost elitist connoisseurship. I get that thrown at me re my Apple habit by ‘woke’ colleagues quite often: I accept the charge, but that is a new line of thought; I do get an aesthetic pleasure from Apple gear.
“new and shiny” does wear off, not so much for me though strangely enough. Epicurius’ point really is not against possessions as such, I would argue, but against the consequences they usually bring: as I said and as I think the Ancients alreasy understood.
I think there is something to his point and these guys are now being re-read quite widely. I think there are strong similarities with Zen and so on as far as I am told. I find the idea often arises in people spontaneously too, often surprising them that there is such a strong historical pedigree.
In my own view it is a idea closely related to Aristotle’s view of finding the ‘middle ground’ where virtue lies. Greed on the one hand regarding possessions is bad BUT monkish self mortification on the other hand, in this case is also bad? The right attitude is sort of 'enjoy what you have and more importantly ‘need’ '. All quite hard to flesh out sadly, especially in an Apple Store 
My apple watch, will go three days without a charge and I have had it for over two years I think. I don’t use a lot of what is on there. I don’t use the ‘fitness’ stuff etc. I find setting and fussing with those settings puts one in that situation where the device is a ‘burden’ in Nietzsche’s sense I might say!
I use my watch for tactile notifications and to open my MacBook and I consider that, along with dead accurate time, with which I am irrationally obsessed 
, to make it worth every penny. Yeah I have steel and chain mail band that I sure as heck don’t ‘need’.
I have had a lot of scathing remarks from my cohort regarding Apple too:shushing_face: I am holding on to my 2014 MacBook Pro till it breaks like Simone: then an iMac, I just don’t like the new macbooks: leaving aside butterfly issues etc… I just don’t like them as much, this one is thin and elegant enough.
