I was trying to think of all the different permutations around this question, there are a lot, and there are no doubt some I have not thought of and do not know.
Are you looking for him to adjust status?
I have come to the conclusion that the Guardian mainly operates on emotions, some, all? of which can be contradicted by reality and then their heads start spinning.
Quite amusing especially when they leave comments open.
A. (F2A) Spouses and Children of Permanent Residents: 77% of the overall second preference limitation, of which 75% are exempt from the per-country limit;
I have yet to come across anywhere requiring proof of legal status.
I am intrigued about all the paperwork involved in getting married as I have not come across that either.