It's a real dilemma...
The nice thing for Aragorn is that you are retired, and spend most of your time within' seeing and hearing distance of him, whatever his situation. (His sisters and brother too, of course.)
Well, when it comes to natural remedies, I did go that route with Boaris, after he ended up with a blockage. He kept getting into dog food, we discovered.
I followed the post blockage additions to his diet for 2 weeks or so, that were in the original book I used to have. (And, rebought the correct edition from eBay, but probably have to re-find and buy again since the whole 2020 'incident.') The same book I used to feed homemade food originally.
After that, I took him off of commercial food altogether, and he went on my homemade diet. Later in his life, when I could no longer make the food for various reasons (lost my 'fridge/freezer and had to use a college 'fridge for a while, for example.) he went back on commercial food.
As a side note, Dh and I were talking about that the other day, and discussing how the cats that we had who were always on the diet, or ate it for most of their lives, lived the longest and healthiest of all of our cats. They averaged 19 years, with a couple a little less, and a couple a bit older. The vet always commented on their longevity and them not needing much of anything from him, though they did get rabies vaccines and exams. I would love to go back to that, since I cooked only once a month or every 2 weeks - depending on how many mouths there were to feed. I made a big batch. Then, just gave them their oils and soaked oats.
Anyway, it really depends on what kind of crystals they are. Which foods that need to avoid, even in treats and sharing with people, etc.
In some cases, people want to acidify with various foods or supplements, for example.
Diet alone is probably not enough, especially when feeding any type of commercial diet, now that you mention it. Some people feed a canned food diet, rather than dry, for example, though I don't think that that alone would address what they need to, depending on type.
Some add supplements such as cranberry powder, or others no matter what the diet is, as is applicable to their pets specific crystals/stones.
Some people push more water by getting fountain bowls, adding more bowls for water around the house, etc. though it doesn't sound like Aragorn is going to need to be bribed to drink! Though, he may have days where he drinks less as he ages.
I think that avoidance of foods that aren't good for their dog's situation is important. I heard about pet parents who gave pumpkin for reasons that people do, and didn't think that it's important to mention it to their vet, because it was only a spoonful per meal. But, in some cases of stones/crystals, pumpkin is contradicted...
It's a difficult thing to decide for you.
If you want me to give you a list of foods that dogs should or shouldn't eat with whatever type of crystals Aragorn happens to have, just let me know!
Love All Life, Thank You For Posting! :)