Yes, Bizum will eventually be replaced by Wero. At least that's the plan. As of right now almost every EU country has it's own instant layment system. Wero aims at replacing and unifying all of them so that you can use instant payments in other EU countries as well.
I believe the spanish banks were part of the initial launch, but dipped out last minute for whatever reason. But I'm pretty sure, once it takes off in Germany and France, Spain will follow shortly after.
For that to be legal I would imagine the uncle would have to have written it in his will