Your son's criminal history can certainly prevent approval of his application depending upon the specific facts. Additionally, it most certainly will lead to delays in the clearance of any background checks.
Consult with an experienced immigration attorney for case specific advice.
While this answer is provided by a Florida Bar Certified Expert in Immigration and Nationality Law, it is for general information purposes only and an attorney/client relationship is neither intended nor created. You should seek out qualified counsel to review your case and provide you with advice specific to your situation. Call +1-561-478-5353 to schedule a consultation with Mr. Devore.
This may be contributing to the delay since background checks are performed. I recommend contacting a qualified immigration attorney to fully discuss your case.
Legal disclaimer: By answering this question, there is no intention to create, nor does it create an ongoing duty to respond to questions. An attorney-client relationship has not been formed. The answer is not intended as anything other than the opinion of the author. It should not be relied upon as legal advice. The answer given is based upon the limited facts provided by the person asking the question. To the extent additional or different facts exist, the response might possibly change.
I agree with attorney Devore. You can retain an attorney to intervene in the case if you are not currently working with one
This is not legal advice and a client attorney relationship is not created. For a free consultation call (718)234-5588.