Read it through once

"I am not sure, but I think it was because his son, Laurie's father, married an Italian lady, a musician, which displeased the old man, who is very proud. The lady was good and lovely and accomplished, but he did not like her, and never saw his son after he married. They both died when Laurie was a little child, and then his grandfather took him home. I fancy the boy, who was born in Italy, is not very strong, and the old man is afraid of losing him, which makes him so careful. Laurie comes naturally by his love of music, for he is like his mother, and I dare say his grandfather fears that he may want to be a musician; at any rate, his skill reminds him of the woman he did not like, and so he 'glowered,' as Jo said."