She, as TPM stated, visits to campus, e-mails, letters, and calls are permissible with a transfer who has received permission from his current coach. However, do you know whether the coach has received that permission yet? Was it forwarded by your son, or did his current school tell you they would send it?
From the tone of your 2nd post, it appears that your son is only looking at one school to transfer to. He may need to start considering other options if he doesn't hear anything in the next few days.