DOesn’t take a handwriting expert to spot the problems. The one that stands out to me is the B on his letter. Who ever signed it used two separate strokes. All of the B’s in the comparisson signitures are a single stroke.
Also, the r’s are very different. His real one is very fluid and crosses back over the vertical in a small loop. The signature one does not and was put in after the fact. That’s why it’s so small. They had to squeeze it in. They also left off the Jr. something he never does.