Hi,
Your brother is on the only drug which has been so far formally approved for ALS. If you look back under that subject - there were numerous posts regarding Rilutek.
Most likely, many will share my opinion, that establishing a good diet IS EXTREMELY IMPORTANT. Yes, it's normal (irony!) for the neuro not to suggest anything in particular - happened to us as well.
Again, if you look back at our previous posts, we have been discussing that in length. The very basic idea is to introduce as much as possible natural, toxin-free foods, drink a lot of water to flush out the accumulated toxins in the body, AVOID at all costs foods containing artificial "stuff," MSG, flavours and a whole lot of other ingredients meant to help long shelf life, preservatives, SUGAR, especially processed white sugar, ALL diet sweeteners, SODAS, red meat, starches should be minimized and so on. Make your juices, instead of buying them. If it comes in a can, box or a bottle, chances are - it's not good for you. Organic produce is better in most instances. Many follow supplement regiments, most of which are self-directed, after we read and read and read, and then little by little we establish a regiment which seems to be OK, or so we percieve it to be.
By doing the above, the body should be made freer of toxins, the diet and the supplements should introduce greater flow of antioxidants which in turn are supposed to help chase the free radicals and thus slower the rate at which the neurons are damaged.
This is the general idea. The more you read, the more you will fine-tune what is best applicable to your brother.