You met your Fiance and he will be returning to marry you
I am not as pessimistic about the wait time but will certainly take time
I suppose it is a positive he was able to travel and reenter
BBC News - Henry Cuellar: US congressman carjacked at gunpoint in Washington DC
https://www.bbc.co.uk/news/world-us-canada-66991932
His main concern seems to be that this happened in an area a lot of senior Democrats live in
He is certainly eligible to naturalise, no need for you to pay.
Working then they are unlikely to be able to enforce the I 864
He may have acquired 40 quarters of contributions anyway.
The I 864 has been used in Divorce Court.
Your best bet is if he naturalises, when did he become a Permanent Resident?
If you cannot afford a Lawyer then I assume there is not a lot he could do anyway.
Are they working?
Well seems she has properties apart from Maryland, made her money in the DIE industry, and has agreed to register to vote in California
per NPR just now