Some of us are old enough to remember when we Catholics were regularly instructed not to attend the funerals or weddings of our Protestant neighbors, relatives or friends. It was an awkward time to be sure because the human heart seeks to be united to loved ones in such moments of great sorrow and deep joy. I believe that it is the grace of the Holy Spirit that urges us to seek some expression of ecclesial union at those moments.
Source: Archbishop Wilton D. Gregory - The Georgia Bulletin, "The love of Christ compels us to reconcile", 26 Jan 2017, https://georgiabulletin.org/commentary/2017/01/love-christ-compels-us-reconcile/ (ALSO IN SPANISH at https://georgiabulletin.org/commentary/2017/01/el-amor-de-cristo-nos-apremia-reconciliarnos/?lang=es)