contact with my half brother after 7 years

i (19f) was not allowed to have contact with my brother (13m) since i was 12 years old. it was a whole case with dhr when we were taken away from our mom. well my stepmom would never allow me to have contact with the side of the family that my brother is staying with. well, my dad finally gave me my aunts number who has custody of my brother. we were always close. but i’m scared he thinks i purposely was not apart of his life and will resent me for it. he was my baby brother that i adored. i miss him constantly but i don’t think it will be enough for him to understand or forgive me. any tips or advice on salvaging my relationship with him?