No. Every employee who is available to drive must participate in a Random testing program. That employee must report for testing when selected.
The regulations prohibit the substitution of an alternate. If the employee refuses to report for testing after being instructed, it qualifies as a Refusal to Test. The employer must report this refusal to the FMCSA Clearinghouse.
He definitely doesn’t want that result, so he needs to go for the test.