The Church would take the position that your brother, as a baptized Catholic, is required to marry in the Catholic form. Going by only the information you have provided, it sounds as if the Church would consider your brother’s marriage to be invalid due to lack of form. Therefore, a full-blown annulment would not be required. That said, there may be other circumstances that we don’t know about that would change this conclusion. Your best source of information would be your priest.
oh ok. His wedding was on top of the stratosphere in Las Vegas so it definitely wasn’t the catholic form. Im slowly bringing him back to the church and was wondering just incase he marries a catholic in the future
Gotcha. Best of luck with that.
You’d definitely want to talk to a priest of your (well actually, his if they’re different) diocese about this. I think the requirements for what happens for a “lack of form” vary from diocese to diocese. Some places you don’t have to do much, but in others you have to fill in paperwork and send it in and get a declaration of lack of form. Even in the latter case, it’s nothing like as complicated as the annulment process and usually takes less than two months. However, IIRC, thy may ask questions on the paperwork like “Have you ever officially joined a non-Catholic church?” and “Have you ever publicly declared yourself an atheist?” I have no idea what happens if you say yes, but it might complicate the process.
Do you pray for your brother every day? Pray the Rosary and ask Mary to lead your brother back to Christ. If you show your brother your love of God and your love for him then the grace of his Baptism will raise the spark of the indwelling Holy Spirit to the flames of Christ’s Passion that will engulf him.