How long to add the new wife of an EB-5 investor to the green card process?

It depends on whether his wife is in the U.S. or in India. If in the U.S. she may be added to his file or have to wait for a period of time thereafter for approval. If in India, she will have to consular process and the time depends on when she can get an appointment.

From your question, I understand your son is in the US and his wife is in India. Since I-526 approval is pending, there are multiple options that you can consider. She can apply for the H4 visa stamp in India and enter the US as your son’s dependent. This may take between five to nine months. Once in the US, she can apply for Adjustment of Status after your son receives his conditional green card. Else, your son can file an I-824 after getting conditional permanent residence and notify the US Consulate in Mumbai about his adjustment of status to permanent resident to enable his wife to follow-to-join in the US. This process may take around 12 months.

It depends on where they are residing. As soon as they have the marriage certificate in hand the new bride should file an I-485 as a derivative linking up to his case provided, she is in the U.S. in a valid nonimmigrant status. If no, then an I-824 needs to be filed to allow her to consular process after he gets his conditional residence.

There will be lots of answers out there, this is something you just make the application and wait for the process, rather than ask questions.

It is hard to tell the exact processing time due to various factors. One of the main factors that could impact the processing of the petition would be the service center that is processing the application. However, in general we have seen to take anywhere from 5 to 12 months.

I am assuming that he has not yet been adjusted to conditional permanent resident. and that she is not currently in the U.S. If so, and he marries her before his status is adjusted, then when his I-485 is approved he may file a form I-824 to notify her consulate that his status has been adjusted to permanent resident. Then the processing times will be however long it takes to approve the I-824 (varies at different locations) and how long it takes to process his immigrant visa (unpredictable).

She can either process for an immigrant visa after your son obtains conditional green card status assuming they marry before that and assuming he filed AOS, or, she can enter the US as an H-4 spouse, assuming your son has an H-1B and she can then file AOS. Either way will take about a year or so.

It's not a simple process, but an amended application would be needed. Your son should contact his lawyer for assistance. If no lawyer, it probably won't happen, and he will have to petition the spouse once he becomes a resident.