You have to realize that the evil one has been trying to divide the Church since the beginning. Sedevacantism is not the answer. I saw a meme today, and it rings true here:
Sedevacantism is just like Protestantism, only with incense.
Don’t fall for that idea that sedevacantism could be consistent with true Tradition. I think we can all admit that there are many Catholics today who have misinterpreted what the Second Vatican Council did. But we have seen this going on for centuries in the Church. We think it’s bad now with some of the controversies we have, but how bad would it be if we had bishops denying the divinity of Christ, as we did during the Arian heresy? Trust our Lord’s promise, that the gates of hell won’t prevail against the Barque of Peter, even if she appears to be sinking. Call to mind what Pope Emeritus Benedict XVI
said at the funeral of a cardinal in 2017:
What particularly impressed me in that last talk with the retired Cardinal, was the loosened joy, the inner joy, and the confidence he had found. We know that this passionate shepherd and pastor found it difficult to leave his post, especially at a time in which the Church stands in particularly pressing need of convincing shepherds who can resist the dictatorship of the spirit of the age and who live and think the faith with determination. However, what moved me all the more was that, in this last period of his life, he learned to let go and to live out of a deep conviction that the Lord does not abandon His Church, even when the boat has taken on so much water as to be on the verge of capsizing.
I will keep you in my prayers during this time, GloriaDei. Cling ever closer to Holy Mother Church at this time. Pray for the intercession of the great saintly popes, including St. John Paul II, as they represented the visible unity we share with Christ, the Head of the Church.
And while I understand what you mean, that your friend is (misguidedly) looking out for your soul, you might also ask your friend what his particular Church teaches on the indissolubility of marriage, and contraception as well. Not to mention, Byzantine Catholics don’t add the Filioque in their recitation of the Creed, so I don’t know why he brings that up. Nostra Aetate is orthodox, but again, certain groups of people like to twist its words, just as certain priests and bishops twisted Scripture to make Christ not appear divine during the Arian controversy.
Feel free to send me a PM at any time, and be assured of my prayers. Do not lose faith in Christ’s Church! Again,
from Pope Benedict:
The Church – and in her, Christ – still suffers today… Again and again the little barque of the Church is ripped apart by the winds of ideologies, whose waters seep into her and seem to condemn her to sink. Yet, precisely in the suffering Church, Christ is victorious…
He stays in his barque, in the little boat of the Church.