I am a NY attorney and cannot advise you as to your state's laws, but I may be able to provide certain general information that may be helpful to you. If I am correctly understanding your posting, even prior to your husband being discharged, his employer had arranged for a successor to your husband.
First, I don't see the relevance of your husband's replacement being a foreign national. I am assuming that the employer is complying with appropriate laws dealing with hiring of citizens of foreign nations; in any event, I imagine that your husband's objection does not deal with who was hired to replace him, but, rather, that he was fired in the first place.
Second, I do not see anything in your posting that suggests unlawful conduct by your husband's former employer. One's rights (even if one is a member of the clergy) in employment are quite limited. If your husband had a written employment agreement, first look to that agreement to see whether any provision of it was violated. If there was no written employment agreement, then the next question is whether there was unlawful discrimination or retaliation, based upon such factors as age, disability, religion (I imagine this is not a factor), national origin, color, creed, or sex.
Your husband should consult with a local attorney.
Good luck to you and your husband.
Michael S. Haber is a New York attorney. As such, his responses to posted inquiries, such as the one above, are limited to his understanding of law in the jurisdiction in which he practices and not to any other jurisdiction. In addition, no response to any posted inquiry should be deemed to constitute legal advice, nor to constitute the existence of an attorney/client or other contractual or fiduciary relationship, inasmuch as legal advice can only be provided in circumstances in which the attorney is able to ask questions of the person seeking legal advice and to thus gather appropriate information. In addition, an attorney/client relationship is formed only by specific agreement.