No UC or CSU requires Calculus but for Engineering students some exposure to the subject is helpful prior to starting at any college.
How are his Math grades? The UC’s and CSU’s require Math placement tests so they will place him an appropriate level course in college.
To start off, what are his UC GPA’s
and CSU GPA’s?
https://rogerhub.com/gpa-calculator-uc/
My older son was an Environmental science major at UC Davis, had taken AP Calculus in HS but Math was not his strong suit and did some review over the summer prior to attending UCD. For his major, he took 2 Calculus courses and one Stats course.
Environmental Engineering will require more Math course’s but if he has a strong Math foundation, it will not be an issue.
He will be evaluated within the context of his HS so if his Math progression is typical, it will not impact him in the admissions process.