He's a devout Catholic and a staunch conservative and we agreed over the last 4 years that the Democrat party is evil. I have two theories. He said his church services were getting political about climate change and didn't the Pope say we have a moral duty to save the planet? If so, that could have changed his mind?
He's also a prof at a Catholic University
Why did he stop speaking to you?
possibly because his work said he couldn't associate with MAGA people anymore.
I have another friend of 25 years that stopped speaking to me after the management of his tech company in SF essentially said that association with MAGA could cost you your job.
Understandable, but your friend reminds me of Esau, who sold his birthright for bread and pottage of lentiles...