Since I think that person (probably the uncle?) He said he want to go far away as possible(I think he wanted to escape in that farm?) And then when the driver mentioned about Little A he looked shocked as if he didn't know what happened as if he didn't have a clue. So my theory here is that, the letter that was given to little A wasn't really from the Uncle but from the organization and prentend that it was the uncle who sent it since the uncle possibly escaped so the organization went to find someone to replace the uncle and do the work.
Since I think that person (probably the uncle?) He said he want to go far away as possible(I think he wanted to escape in that farm?) And then when the driver mentioned about Little A he looked shocked as if he didn't know what happened as if he didn't have a clue. So my theory here is that, the letter that was given to little A wasn't really from the Uncle but from the organization and prentend that it was the uncle who sent it since the uncle possibly escaped so the organization went to find someone to replace the uncle and do the work.