From my perspective, I need deadlines spelled out. Something along the line of “to have the best chance of getting aid, I need to be applying by Nov 1. So can we sit down by Oct 15th?” Not sure what those dates would be for your area, but I know that I am more likely to act if there is a deadline and repercussions for not acting.
An alternative is perhaps going to a cash 4 college workshop? I know very little on UC system, but found a note that they provide assistance completing the FAFSA paperwork. A group setting might help. But again, since people tend to put things off, see if your mom might be willing to attend an earlier date - the site says they start in October.