“The Pigman” from Paul Zindel.
2) Lorraine and John are treated very friendly by Mr Pignati. Their parents don’t treat them so and often quarrel with them. I think Mr Pignati is so kind because he is lonely and his wife has gone to California (later, the reader finds out that she is dead and Mr Pignati mourn for her).
3) They are very impressed of the big house with all its furniture and junk. They think some of the things might be very expensive so they don’t want to touch anything. John’s and Lorraine’s family aren’t very rich and so they think that Mr Pignati has a little fortune.