dream carrier
A person who is willingly living out the dream of another person who is unable to fulfil the given dream for any reason. They can either bring a dream into reality or finish what was already started. A dream carrier does NOT throw aside their own ambitions to fulfil those of others but instead uses them to increase their own personal drive to accomplish the goals that were set.
MLK Sr was an early figure in the American Civil Rights Movement. His son, MLK Jr became his dream carrier, and he finished what his father started.