Lwr, based simply on the existence in your collection of the 'Encyclopedia of the Colors ...', I would say that your brother might have spent serious money on stamps. As such, the first thing would be to post here detailed pictures of ALL stamps from the albums - a rule of thumb, older and more basic a stamp looks, the higher might be the price of it (with stress on "might")

Once you post the images, the very knowledgeable people of this forum will be able to say 'yes, it's worth', or 'not'. From there, your options will be much clearer - dealers, auction houses, etc.
PS: If you decide to sell the 'Encyclopedia of the Colors...' then I am interested
