Theo knew that the suitability of a hearing aid as far as Greg was concerned wasn't in it's ability to make everything audible, but to let him understand people without being bombared by world full of noisy cacophony, something that Theo was used to tuning out (at least in his conscious mind - his paranoid subconscious was always tuned, all the time, to everything) but that Greg had never had to do. That Greg actually liked the thing had it high in Theo's estimation and the smile that brought to his face was sincere.
He tilted his head as Greg spoke wistfully, and Theo felt badly about the fact that his friend wanted to go and do things but couldn't, whereas he could do those things but was too anxious to try. The idea of a full blown professional Quidditch match, being among all those screaming shouting patrons, the giddy whirlwind of colours, the crush of bodies and the announcer's voice over it all made him feel a little panicky. His fingers moved seemingly of their own accord to pluck absently at the hem of his jumper. "I don't see why not." he said, encouragingly. "Maybe you could even ease into it. One hearing thing on at a time, that kind of thing, so that it doesn't come as a shock all at once."