If you really want to help out your son, help him hire a good criminal defense lawyer who can sort this out and maybe, just maybe, get a resolution that does not mess up the rest of his life.
Answers on Avvo are for general information purposes only and should not be relied upon as legal advice. No attorney / client relationship is created by providing this answer. For specific advice about your situation, you should consult a competent attorney of your choosing.
The officers would have to show that it was apparent that they were police officer. Additionally they would need to show that there was an actual evading. Here it is a misdemeanor. Of course it is an odd time to be out walking around on someone else's property. Nothing good happens at that time of morning.
Bobby Barina's answer to a legal question on Avvo does not establish an attorney-client relationship. Mr. Barina offers everyone a free consultation to discuss their case. Feel free to call his office at 254-699-3755 to make an appointment or visit his website at www.bobbybarina.com for more information about his services.
Ask your son's attorney about inquiring whether the D.A.'s office will "divert" the case, if they will consider such relief, short of a trial. It sounds like your son has no prior record, was not otherwise committing any offense (other than a thin beef of "criminal trespass" of the property), but did run from the police. Some considerations a good attorney will examine is whether the police car was marked or unmarked and whether the officer used any emergency lights or audible police-type sounds to identify police presence. The "divert" is an entire explanation by itself, but should be examined as an alternative from what I am reading here.