Since the IRS is closed to telephone calls, there's nothing much you can do. If your child filed and said no one one else could or did claim him as a dependent in 2019, and he provided bank information,and he receives no check, he will likely have to wait until next year when he files his 2020 return to receive his stimulus. It's certainly possible the IRS may go back and try to correct some errors or oversights before that but we have no way of knowing.
