I thought that I would bring this up to date for anyone who might have a similar issue. I have great news! Upon advice of an immigration lawyer, my son-in-law decided to go ahead and apply for citizenship. He had his interview this past Wednesday. Everything went well, and he was sworn in the same afternoon. I hope that this will serve as encouragement to others who may be in the same situation, which their lawyer says is very common.
#1suegra got a reaction from Jessica Donahue in "Involuntary separation" and applying for citizenship