At its core, what is our brain doing to cause us to experience emotions? Can that (neurons) be expressed mathematically? If so, what’s to say that math can’t experience emotions?
At its core, what is a mass doing to cause gravitational attraction? Can that (distortion of space time) be expressed mathematically? If so, what's to say that math can't cause gravitational attraction?
Depends how you define "emotion", but I imagine the grandparent is assuming a definition along the lines of "neurochemical reaction to stimulus that affects mammalian consciousness in a way that affects heart rate, perception, skin temperature, blood flow to different parts of the body, etc."
There's isn't a mathematical model of how thinking works, let alone of the entire organism. So no, respectfully. A theory that thinking equals math and so math must at some point equal thought (and then emotion) remains inhibited by the first unproved statement, at the least.