Green card

Here is a question I have. We have lived in U.S. for 15 years. Hubby has dual citizenship, I kept green card. My son decided he wanted to go back to Canada and gave up his green card. Now he would like it back. What do we have to do to get his green card back? does he have to start all over? Can my husband sponsor him? He is an adult 27.

Your husband will have to sponsor him with form I-130 plus whatever it says to include with it.

It'll take several years and it can only be done as long as your son is un-married. If he is married now, or gets married sometime during the processing time (about 5 years I think currently) your husband cannot sponsor him and he will have to figure out some other avenue to get to the States.