@wpmomfl I don’t think it’s really worth your effort. At this point, most of his questions (about admissions) have been answered, and he’s already done the tour. Once he’s accepted, he’ll have to attend the two day orientation, over the summer. He’ll get a LOT more info out of that (and it’s covers much of the same info as the open house event).
What he may want to attend in the spring, are the specific college tours (like Engineering or Honors program). Once he’s accepted, they have some additional student events in the spring, I know engineering has a one day event (around April) for accepted students.
You do NOT need to update the SSAR with his senior grades. UF will use the SSAR (8/9th thru 11th grade) to determine if he’s accepted. If he is accepted, UF will request his final High School transcripts. If you do poorly (think D’s or a bunch of C’s) in your senior year, UF “may” rescind the offer of admission.
In other words, he should keep your grades up (a few B’s are fine!) and try to have some fun before he graduates high school. 
Good Luck!