Agreed with the Leadership Alliance. He can also go to the NSF website and look up REUs - here are the biological sciences ones (https://www.nsf.gov/crssprgm/reu/list_result.jsp?unitid=5047).
I would recommend that he not limit himself to the East Coast unless there’s some specific reason. When he wants to go to a PhD program, he will do better off if he leaves himself open to anywhere geographically. The best program for him might be on the West Coast or Midwest or South or wherever. It’ll be good for him to have a summer experience maybe outside his comfort zone and potentially a really good, well-known professor in the field.