So you have the approved LMIA? He applies and show that he is the only one experienced enough to do the job. He will need employment letters to prove he has experience in the NOC, and depending on the NOC, ECA and IELTS too. It will be heavily scrutinized because he is your brother so can’t tell you chances.
If you are the business owner, then do it yourself. Follow the requirements on the IRCC webiste for applying for a LMIA. Your business must meet specific requirements for size, number of employees etc. The first step is posting the job on Job Bank, Indeed etc. Then if you have people, apply and are experienced you must document why they are not able to do the job. Since your brother’s NOC is civil engineering then assume your job is for a civil engineer. That is a licensed profession so you must prove why you aren’t hiring a Canadian P.Eng but someone who isn’t licensed.
