Ultimately, we are all called to follow the Church’s teachings.
It is important to keep in mind 1. Everyone is in a different place in their faith journey. 2. We are all called to help and support our brothers and sisters in Christ, and help them stay the course.
With that being said. If I observe someone doing something that is against the teachings of the Church, there are a few ways it can be handled. 1. I could approach them in a kind and loving way, and say something like…“I noticed you did this, or that. I am having trouble understanding why you did this. Could you explain it to me?” 2. Tell your pastor, or Bishop and rat them out. 3. Come down on them like a ton of bricks and tell them to stop immediately.
I think you can see by those examples, that number 1 would probably be the best approach. It isn’t accusatory, so it is less confrontational, and should open up congenial discussion which could lead to correction. (I know, sometimes I live in an ideal world where everything is perfect…lol

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Now, as far as people not following all of the teachings of the Church, are they still Catholic?
It is not for me to judge that. That is between them and God. They have to answer for that someday, I don’t. I also don’t know if it is something that has been corrected, or even addressed in reconcilliation, so again, it isn’t for me to judge.
On a personal note, I will admit that I
struggle sometimes with the church’s view on artifical insemination, or invitro-fertilization.
One one hand, I think it is a wonderful gift to aid in bringing a life into the world to a family that desperately wants children. Then I think about God’s will. God must have a plan for them if he has chosen for them not to have children naturally. Maybe it is his will for them to adopt one of the many many children with no parents.
I often discuss this in confession, but I always, always, always, uphold the church’s teachings on the issue.
Something else to remember is that even though a person may stray, and engage in birth control, artificial insemination, etc. There is always a way back. Reconcilliation.
I do know of a case in our parish where a gentleman came to me about being a sponsor for a candidate in RCIA. (I am the lay director for RCIA) He disclosed to me that he was living with a woman outside of marriage, and they had children together. He also told me that all three of our priests would no longer grant him absolution for that particluar sin, because he did nothing to resolve the situation (ie marry the woman). Regrettably, I had to refuse him the role of sponsor based on this, but that doesn’t mean I judged him, I merely upheld the teachings of the church. Is he still Catholic? I don’t know.