Be aware that at the UCs and USC, intended major or division (letters and science, engineering, etc.) can affect admission selectivity. For example, applicants to Berkeley EECS or bioengineering face a higher level of selectivity than those applying to the Berkeley College of Letters and Science. UCSD has several impacted majors; some applicants to those majors have reported getting admission as undeclared, which means that they would have to apply into a competitive admission process to get into the desired major later.
Caring for other family members out of necessity does count as EC or work, so he may want to include that experience in his essays. Baseball would also count as an EC, particularly when he has achieved to a fairly high level before the sport-ending injury.