I sent my son to a private English daycare for about 6 months for a more dedicated ramping-up in a very small group environment and he learned basic communication there. We, parent also tried to help him to make friend with other chinese kids who speak both English and Chinese in the neighbourhood.
Let him watch English Children's movies. Kids pick up a language really fast, much faster than we can anticipate. They could overcome language barriers in 6-12 months.