This board does have a policy, against self-medication. Furthermore, I get that he'd your child, and all, and I know you'd always want to do your best for him, but ethically, preparing a treatment for someone else, when you're not a physician, is dicey -- you're trusting that every possible side effect he's feeling, he'll be able to communicate to you, and you won't miss the significance of even the most casual observation, and that's hard to do, without training.
Within that framework, if you can find a sympathetic physician, and you can get the raw herb, to make a tea out of, maybe you'll see something of the benefit, and can work with the physician on better sources.
Since this is purely academic, I haven't gone searching for gotu kola, and it's active agents. Alkaloids, by definition, do tend to dissolve better in acid water, but other organics tend to need a better solvent. But how much, and what kind, to dissolve a particular component, and who concentrated the active becomes -- that's all different on a case by case basis. You need a professional.