Inviting My Parents and Brother

Hello Everyone, I am a Canadian Citizen and want to Invite my Parents on a Super Visa and My Younger Brother on a Visitor Visa for my Civil wedding Ceremony. My dad was previously denied for a visitor visa, My mother had a visa but she never visited due to some family reason. My brother was denied a study permit previously 3 time and 1 visitor visa was denied stating that He will not be returning after his study or Visit.

Moreover, My brother is in UAE and working there full time now and will be returning to his work after the Visit. I am already meeting the income criteria to invite my parents on Super Visa.

What are some suggestions I should be following as this will be a special day and I really want them to be here with me. Is it recommend that I apply by myself or should I seek professional help ? If anyone has any sample invite letters that I can use, can you please share those as well ?