..from the inside?

I know I could look online and find all sorts of semi-scientific theories, but I think what I really want to know is why music would sound good to 'tone deaf' folks (using the term as a broad generality)
I'd like to know what people here think about how to help them Hear..or whether you think it's a hopeless cause.

Also, what's it called when it's timing/rhythm instead of tone?

Thanks,
M