From a reader:
Is it wrong if not in fact sinful to attend the weddings and funerals
of non-Catholics? For as Pope Pius XI stated in his encyclical
treating on Christian unity, Catholics are never to participate in
schismatic or heretical congregations. I would love to know what you Father have to say in regards to this.
Yes, a Catholic can attend a non-Catholic wedding of non-Catholics marrying in their own non-Catholic church service. You can attend non-Catholic funerals of non-Catholics as well.
But you cannot participate in any form of “communion” they offer.
Go, and be respectful of what they do. Say your own prayers quietly for the people involved if you need to. And you don’t have to be a party to anything stupid, or blasphemous.
The encyclical referred to, above, is certainly Mortalium animos, which I drilled into in one of my PODCAzTs.