I think there's mixed views. Seoras has always held that a Prophet never declares himself a Prophet. Mathurin didn't. Nor did any other ESA prophet (nvm that one was posthumous). They were acclaimed by the faithful. That was a part of his objections to Jonsu and Alaster declaring themselves prophets. So, Seoras has never stated he's a Prophet. He's never made a deal out of being superior in balance or anything of such. He just shares his insights. Within the religion, his rank is Penitent Protector. There is a Prophet rank (from when Malus was around), but he doesn't hold it.
However, he does take a guiding hand to different nobility throughout Dwilight, whether they are Church members or not. He was a priestly emperor who gave up imperial, royal, ducal, lordly power to preserve the church under Mathurin's teachings. He did die and return from death while a religious leader. Old SA did admit he was right after all about Alaster after they gave Alaster a pass. So some within the Church do call him or otherwise treat him as a Prophet or His Holiness. It's something that has gradually increased over time.
