This was a private conversation between an irate, slightly senile old man and an irritating little skank. Frankly, I’d heard worse yelled during lovers’ quarrels.
I think the line would have been crossed if he had deliberately set out to make his racist views public. As it stands, he didn’t cross any line. The person or people who leaked the conversation crossed a moral (as well as possible legal) line.
If she taped the discussion without consent and leaked it, hope she does some time in jail for it.