Not knowing the circumstances and how many brothers, Yes $10k is better than a poke in the eye thou a bit on the lean side but hey it was his win and if it was my brother I would not be complaining.
Yes I would be inclined to keep it hushed, I would still help people out but they would not know where the money came from or how much I had.
Slightly different note, I have on occasions brought lotto tickets as a present. One of my brothers said he would never buy some one a lotto ticket as a present, when asked why he said "what if it's a winning ticket?"