son admitted as transfer to UCSB Psychology/Brain Science Pre-Major, Pre-Calc in Progress is shaky

Hello all- could really use some advice! BACKGROUND: My son took a few gap years as a sponsored athlete, then got serious about school and went to a CC for a few years and then applied to UC's last fall as a transfer for Fall 2016. Because he is a little older due to GAP years (just turned 25) and just because of his personality, he has not allowed me much input into any of his decisions re where to apply etc. (Another family member was supposed to help with finances along with financial aid, so I couldn't play that card.) He is also LD but has learned to manage that pretty well, works very hard, advocates for himself, utilizes accommodations etc. Against my advice and much to my chagrin, he did not apply to any safety or back-up schools. As stated above he has been accepted at UCSB, and approved for UCD TAG as a Psych major, but still waiting on their admission decisions. (Has also applied to UCSC, UCSD and UCLA.) The problem is that he is currently in the second half of pre-calculus and has Calculus planned for the summer. Pre-calc is not going well. He has to get a C or better in it, I believe, as well as in the Calc planned for Summer, as a condition of his admittance to UCSB. He doesn't know what to do or what will happen if he drops Pre Calc, or stays with it and gets below a C. I think he is afraid to call the admissions office and discuss it with them. It looks like the Psych/Brain Science major at UCSB includes a lot more math than the Psych major at Davis. I believe that is why he was advised to take the current semester pre calc and summer calc, so he would possibly have other options in case he didn't get admitted to UCD. I am even wondering if he should find a few CSU's that are still taking apps and apply there in case UCSB rescinds and he doesn't get into UCD. I am also worried that the math heavy Psych at UCSB would be too much for him even if he manages not to get rescinded. Any insights welcome! ~ confused mother