Your question seems a bit inconsistent. It sounds like he would be inadmissible under 212(a)(9)(C) because of the illegal reentries. I recommend seeing a lawyer to analyze the case and determine what ground of inadmissibility applies and when he is eligible for a waiver. Depending on the ground of inadmissibility, you may want to start the immigrant visa process now. In some cases, it may make sense to wait to start the process.
Please note that this response for informational purposes only and does not create an attorney-client relationship.
Yes, he would need a waiver. Hire an immigration attorney. You will be hard pressed to handle that on your own.
The information contained in this answer is provided for informational purposes only, and should not be construed as legal advice on any subject matter,not should it be viewed as establishing an attorney client relationship of any kind.