No response from swim coach

My S is a junior and would like to swim at a D3 SLAC near a city, and he’s very interested in Pomona College. ACT as a sophomore was 34, current GPA 4.0 (unweighted), and AP Chem 5. According to collegeswimming.com, his best events (distance) rank him 4th against 2016-17 times but 2nd comparing his Fall times to 2017-18 times. This Fall he filled out the recruiting questionnaire at Pomona and received a response from the assistant coach which was nice. He later emailed the assistant coach an update of his times but didn’t hear back. About 3 weeks ago, he emailed the swim coach to ask if he would be around in April so we could buy our plane tickets to visit, but there was no response. Does this no response mean anything? Should we just assume the coach will be on campus in April? Thank you very much for any advice!