In his answer to your question Dr. Monzer Kahf, Scholar in Islamic Economics & Financial Expert, who stated,
I believe that you are the winner not the loser. You are gaining a lot of love, Du`aa’ and reward from Allah Insha Allah. Those who do not contribute are in fact the losers. Do you want to be a loser too?
My suggestion is to continue what you are doing, also make correction on what the other siblings do of negligence and handling of parents’ money as much as you can but politely, be nice to other siblings and please your parents.
May Allah guide all of us to what pleases Him!