Oh my...it's always so hard to hear about young ones suffering. My husband had MS, and it's hard enough on us trying to make decisions about his care. I'm sorry you're dealing with this.
I don't know whether you should start medications or not. My husband is on copaxone, and we're very pleased with it. I don't know if it's an appropriate medication for kids, but it doesn't have nearly the negative side effects that the other medications do. We felt much safer with it for my husband. It took about 6 months before we saw a change, but then there was marked improvement.
We're also strong believers in the diet connection, and this may also be something you'd be interested in. We originally wrote off the diet stuff as quackery, but we eventually became desperate enough to try it. We figured there wasn't any real harm that could come from it, so why not. We're on the Best Bet Diet (which you can check out at www.direct-ms.org). It limits saturated fat and sugar. And it eliminates gluten, dairy, and legumes. We also eliminate foods that my husband has a personal sensitivity to. It's quite restrictive (and we don't cheat), but we have had a very good experience with the diet. It took us about 6 months to see much of a difference, and it took us about a year to develop the skill of actually being able to track which foods might be bothering my husband. But we're total believers now.
I've recently started a personal blog where I've been posting recipes (a lot of Best Bet Diet recipes are kind of bland, so good recipes can be kind of hard to come by). If you decide you want to try the diet approach, feel free to check it out (http://multiplesclerosisrecipes.blogspot.com/), although there are a lot of MS recipe sites on the internet.