Your husband is facing serious charges. We don't know from your posting if he was released on bail and fled the country and if so, at what stage of the case had been reached. For example, it is possible that if he was read what are known as Parker Warnings, he may very well have been tried and convicted in absentia.
Whatever the situation, your husband absolutely needs to call an experienced criminal defense attorney who has handled violent felony cases in Westchester County or New York City to guide him on his options. Use the Avvo find a lawyer function to locate such an attorney.
Answering this question does not create an attorney-client relationship between us. The answer given is for informational purposes only and is not a substitute for contacting an attorney licensed to practice in your jurisdiction and obtaining legal advice from such an attorney.
If he has a way to get admitted to the U.S., he can arrive, and expect to be detained at the airport based on the warrant.
The above is intended only as general information, and does not constitute legal advice. You must speak with an attorney to discuss your individual case.
He should hire an attorney to negotiate his surrender and begin working on putting together a good bail application. He should expect to be detained at the port of entry.