How is the old man whom Jonas meets different from the rest of the community?
I believe that this question is asking about an event that occurs in chapter 4. On this particular day, Jonas is volunteering to help out at the House of the Old. He interacts with various elderly people, and there is a brief description of how the inside of the building is furnished. The text tells readers that each room in the House of the Old is comfortably furnished, and the floors have carpet. We are told that it is a "serene and slow-paced" place. The narrator also points out that the overall feel of the place stands out in stark contrast to the busier manufacturing and distribution centers that are common to the rest of the community.
It is possible that the "old man" that this question asks about is the Giver. If that is the case, then chapter 10 contains details about Jonas first meeting him. There are some small details about this house that stand out as different than the rest of the community. One such detail is that the Giver's room is locked. The text is sure to mention that "no doors in the community were locked, ever." A few paragraphs later, readers are told that the Giver's room was very similar to other rooms that Jonas had been in, except that the room wasn't nearly as utilitarian.
All of those things were in this spacious room, though each was slightly different from those in his own dwelling. The fabrics on the upholstered chairs and sofa were slightly thicker and more luxurious; the table legs were not straight like those at home, but slender and curved, with a small carved decoration at the foot. The bed, in an alcove at the far end of the room, was draped with a splendid cloth embroidered over its entire surface with intricate designs.
The final, key difference in the room is that the room contains many books. Jonas's house has only three books, and we are led to believe that is the same with everybody else's house in the community.
The books in his own dwelling were the only books that Jonas had ever seen. He had never known that other books existed.