Didn't Rafa once say that the moment he and Toni parted ways is when he retires from tennis? Could be wrong though.
It's not 'parting ways' if Toni is just working primarily at their academy
Bear in mind that Nadal in the past had no clue he'd open up an academy when he did
And I think it's sort of irrelevant, Nadal has been on tour long enough with Toni that if he plays a season or two on without him it's not like he'll be missing out on some key hidden info or tips. And honestly especially playing at an old age it might be good to have someone else around as far as advice and tactics