Sorry for your losses.
If you desire, you may appeal the classification of your brother's actions taken that earned him the Silver Star with the V cluster (I'm sure you know, but for those not in the know that the "V" is for Valor under enemy fire), the actual operation, location and timing will tend to be at a classification that will never be declassified. The appeal should be directed to the Chief of Naval Operations with "copy to" both of your U.S. Senators, and your congressman/congresswoman. It may take a couple of years to move through the review process, which is why you send a copy to both Senators, and your congressman, so you can call their offices if you do not hear back from the CNO's office in two months.
I am not guaranteeing that you will ever get an answer back, but I would file the appeal sooner rather than later. Also, in your letter, please list all of the military background that your family has, and if you still have contact with anyone with Flag rank, they may be able to help your letter process faster.
God bless your familyn and bless your Journey!