ZACK by william bell

I have finally finished reading the book ZACK by WIlliam Bell. The story is about a grade 12 teen named Zack LAne who finds a tresure box in his backyard. The name written on the box is Richard Pierpoint. ZAck researches about Richard; he finds out that Richard was a slave and finds some info about the nugget that he found in the treasure box. ZAck wants to know if he is related to Richard. SO to find out ZAck secretly goes to Natchez to see his granfather when his parents at a trip to Montreal. The reason why Mrs. Lane Zack's mother doesn't like to talk about her dad is becasause Lucas (grandfather) didn't want her to marry a white colored person. This made her to break up with her family. However at the end the two families reunite and lucas changes his thoughts on white colored people. I dind't like the ending because Lucas goes back to Narchez to live by himself,and nobody asked him to stay with them. However i didn't find out if Zack is related to Richard or not, i don't knoe if the mentioned it in the book or not but i didn't noticed it.