Legal Question in Criminal Law in California

What you 'want' is irrelevant, no one 'wants' to be arrested or have to go to court or jail.

Either he appears in court, or there will be an arrest warrant issued for him, enforceable throughout the US if he comes in contact with any law enforcement or any customs officers at the border. He should talk with an Iowa attorney to see if the attorney there can make appearances for him without the defendant personally present. And don't try to defend this in Iowa with the CA weed card, that card is a joke everywhere outside CA; plus, drug possession is still a federal offense. As an example, the DOJ recently ruled that possession of such medical weed cards is cause for denial of firearms rights, under the 'illegal drug user' category of prohibited persons.