There isn't a patron saint of maths tutoring as far as I know, but if there was one, it would have to be René Descartes, one of the greatest mathematicians and philosophers of all time. His best known philosophical statement, "I think, therefore I am", is well worth thinking about. But he also invented the idea of doing geometry with (x,y) coordinates, which forms a key part of the GCSE and A-level maths courses. They are called Cartesian coordinates after him.
There has been speculation that Descartes came up with the coordinate idea as a result of an episode of exploding head syndrome, but if that's true, he emerged from it in a much better state than one might imagine from the name. He eventually came to a sad end, though. He lived in the 17th century when there was no central heating, and unwisely accepted an invitation to move to Sweden in the middle of winter to start a scientific academy and to tutor the Queen.
The tutoring did not go well. Descartes and the Queen did not like each other, and after he had seen her only four or five times in her cold and draughty castle, he caught pneumonia and died, thus becoming, quite literally, a martyr in the cause of tutoring.
So tutoring can be fatal - at least for the tutor. However, I have no plans at all to move to Sweden at any time of year, or indeed to have my head explode, so I hope to be available for online one-to-one A-level maths sessions for the foreseeable future. Please contact me if you're interested.