Are you suggesting that the American Academy of Pediatrics approves of a mother breastfeeding her nearly four-year-old boy?
It does indeed provided that it is still mutually desirable. However, please don’t take my word for it, contact them yourself, but out of courtesy, please post the response you receive here for all to see.
Yes. At that age the child will be eating quite a lot of other foods but there is nothing wrong with breast feeding at that age. When children self wean it is usually between the ages of 3 and 4.