When he is a USC he can file for his wife and an immedite visa will be available to her. Sounds like he has about one year. He can go ahead and file the I-130 now so that it will be approved. He can then file the I-485 and get the category changed once he is a USC. This will speed up the process.
However long it takes for either him to become a US citizen, or for the petition's priority date to become current.
The movement of priority dates cannot be predicted.
For the latest visa bulletin see http://www.engnishimura.com/priority-dates/current
J Charles Ferrari Eng & Nishimura 213.622.2255 The statement above is general in nature and does not constitute legal advice, as not all the facts are known. You should retain an attorney to review all the facts specific to your case in order to receive advise specific to your case. The statement above does not create an attorney/client relationship. Answers on Avvo can only be general ones, as specific answers would require knowledge of all the facts. As such, they may or may not apply to the question.