I only know that when I'm having other candida symptoms flare up, I usually, but not always, also have flare ups with poor circulation in my legs. But not always, so I'm not sure of the connection.
A correction, to keep visitors to your post from being confused: candida is a yeast, it is not a bacteria -- the products that your son is taking are probably antifungals, not antibacterials (you had first used one name and then the other, but they aren't the same "bug").