Thanks for your inquiry. A few things are clear, this process takes a long time and it is really confusing. No one ever seems to know exactly what is going on and I am sure that you and your spouse are quite frustrated. Let’s discuss the basics on processing and perhaps this will give you some answers on what to expect.
I am making a few assumptions when it comes to your inquiry. I am assuming that you are a US citizen or a lawful permanent resident, that your spouse has an approved immigrant visa petition (Form I-130) and that he had spent some time in the US in a period of “unlawful presence” and that is why he is applying for the I-601.
Assuming these facts to be true, your spouse would have been scheduled for an immigrant visa interview before the US Consulate (USCON) in Juarez. This interview will generally result in an initial denial of the immigrant visa application because the applicant would be deemed to be “inadmissible” to the US as a result of the period of unlawful presence that he spent in the US prior to leaving to return to Mexico to the scheduled appointment at the USCON.
Once the visa application is denied, an opportunity is provided for the applicant to file a waiver. The waiver is an application which would permit the applicant to return to the US despite being determined to be inadmissible. In this case, your spouse would be applying for an unlawful presence waiver through submission of the Form I-601.
Now an important thing to keep in mind here is that the USCON makes an initial determination as to whether the visa applicant is admissible to the US or inadmissible. However, when it comes to waiver applications, these are generally handled through the USCIS foreign office. In this case, USCIS has a very busy foreign office in Juarez by virtue of the number of applicants for immigrant visas that are received at this post and the high incidence of waiver applications needing review.
So the initial determination is made that your spouse is not eligible for a visa because of the unlawful presence problem. His waiver application is received and then forwarded to USCIS. The Consular Officer works for the US Department of State. The USCIS foreign office is under the jurisdiction of the US Department of Homeland Security. While both agencies are involved in the ultimate decision as to whether your spouse can return to the US, both agencies operate under their own rules and both have distinct functions to serve.
In this case it sounds as if your spouse may have been scheduled for his initial interview before the USCON and that he was denied issuance of the visa as explained above. My assumption (again) is that the Form I-601 was taken and sent to USCIS for processing. Perhaps a subsequent interview was held by the USCIS officer on the I-601, but this is not explained in your inquiry so it is difficult to tell. There are some programs in place at the USCON and USCIS office in Juarez to speed the operation of adjudicating many of these waiver applications because of the volume encountered at this post. However, I cannot tell if your case is one that is being processed through any expedited procedure in place currently.
USCIS announced in January 2012 that it was considering making the rules applicable to cases like this somewhat more flexible by permitting adjudication of the waiver application (I-601) here in the US before your spouse would be required to return to the USCON. But this procedure is still in the planning stages and it is not currently being employed by any USCON anywhere around the world.
If you have an attorney, make an inquiry and be patient. Most attorneys who handle this work and are familiar with the process and procedure will have explained exactly what to expect along the way. Be patient, these cases often take some time to work through.
Your lawyer knows the case. We do not so we can't answer or make a guess with no background info. It's common for even lawyers to not know what the Consulate is doing. The Consulate does a lot of things with out informing the applicant or their lawyer of their reasons.
Legal disclaimer: This answer is offered for informational purposes only. It is not offered as, and does not constitute, legal advice. Do not rely on this advice without speaking to an immigration attorney in detail about your case. This message does not create an attorney-client relationship.