Hello, I am the only active member in my family and I was wondering if I could get sealed to my deceased brother in the temple without my parents.
What you are asking in an impossibility. Only two types of sealings that bind families together are performed in the Mormon temples. In one type of sealing, wives are sealed to their husbands, in the other one, children are sealed to their parents. I would suggest that the thing to do would be to pray constantly to your Heavenly Father that he would soften the hearts of your parents to the point that they would feel good about renewing their activity in the Church. When that occurs, they could then prepare themselves to be sealed together for eternity as husband and wife. At the same time of their sealing you and your deceased brother could be sealed to your parents.
I would suggest that that could be an active plan of yours. I would not suggest that you try to convince your parents to return to activity. When children try to advise their parents on what they should do with their lives it is generally counterproductive. But if you continually, day after day, plead with the Lord to touch their hearts, it will eventually happen.
Let me tell you whereof I speak. Although my mother was a faithful member of the Mormon Church, my father was a Presbyterian. When I served a mission I was extremely anxious that my Dad would join the Church. I tried to preach him the gospel and convince him to become a member of the Church in all my letters home during my mission. (I later found out that he only read the travelogue parts of the letters). So I decided that I’d stop appealing to my father and begin appealing to the Lord. This process went on for several years. Then, on one occasion my parents came to visit myself and family. (At the time they lived in Idaho and we lived in Ohio).
The day before they left for home, out of the blue, my father asked me that if he were to get baptized could I baptize him. I was given permission from the Branch President and on the next day, Sunday afternoon, we went to the YMCA swimming pool in downtown Columbus, Ohio, where I was able to baptize my father and confirm him a member of the Church. Later that day during the Sacrament service the branch president announced from the pulpit that since today was the 15th day of May, the day of the restoration of the Aaronic Priesthood, it would be appropriate to ordain my father a deacon. So in the meeting I had the privilege of ordaining my father a deacon in the Aaronic Priesthood. The branch president then asked him to pass the sacrament with three twelve-year-old deacons. (I was sitting on the stand, and had the great privilege of receiving the sacrament at the hands of my father).
That night he and my mother boarded a train for home, and that was the last time that I ever saw my father alive. He passed away suddenly about nine months later. A year after that our family was sealed together in the Salt Lake Temple.
So, if it could happen to me, it could also happen to you. Be believing and keep the faith.