i am so, so sorry for your loss - not just your brother's passing - but that he was taken from you so early in life - when you were the one who had most loved and nurtured and given to him. please believe this - that anything good that he was able to accomplish and achieve in his life - including the relationships with his wife and children - are a tribute in large part to the positive input and influence that you gave during his most impressionable years.
i hope that you will not be offended if i paraphrase Jesus - "Greater love has no one than this: to lay down one’s life for one’s (brother)." though you did not literally sacrifice your life in the sense of dying for him - you did sacrifice in a sense that you did lay down your life in so many ways - and gave up so much for his sake. and your sacrifice, painful though it was - did produce a wonderful life for him. i hope that is some comfort to you.
We are often troubled, but not crushed;
sometimes in doubt, but never in despair;
there are many enemies, but we are never without a friend;
and though badly hurt at times, we are not destroyed.
- Paul, II Cor 4:8-9