VisaSaurus

And I just wanted to emphasize that once you file to adjust from within the US he can't travel until the AP is approved.  I don't know how long that is taking currently, but it's months and months.  So if something happened to his parent in that time he'd be not able to leave (well, he could leave, he just couldn't come back again).  You could also marry and not file any paperwork yet, if the sick parent is at a critical stage.  You'd be married, and he'd be on his H-2B and nothing would change*
(*I'd take others advice on this too - by marrying alone you shouldn't show immigration intent so should still be fine on the H2-B.  I believe!)

You do not have to wait 90 days. If someone has told you about a "90 day rule", they are wrong. It's a very persistent myth. 

There is no 90 day rule

When the I-129F arrives, the receiving person will scan all pages to PDF.
 
That person will not be your friend if you send what you described.
 
Keep it complete and simple.

Tips for Filing Forms by Mail | USCIS
I would not send documents in sheet protectors.