Can a motorist fill out the required vehicle repair data form or does it have to be a repair tech?

my moms car failed the emission test but my brother fixed the problem hes not a repair tech he just knows a lot about cars they gave my mom a form to be filled by a repair tech since my bro fixed the problem can he fill it and will she be able to get a retest what i want to know does it have to be a repair tech that fills it out