Charles of Naples ascended to the throne to Spain during the 7 Years War. By treaty and agreement, he was to leave Naples to a second son.
What if that son died or Charles changed his mind and wanted to reunify the old joint Kingdom of Aragon?
France was desperately courting Charles as an ally at this point against Britain/Hanover. Austria was desperately fighting Prussia.
Could a deal have been struck?
Say, Spain/Naples enters the War against Britain early. In exchange, he gets to waive past treaties and keep Naples as well as Spain?
France gets an ally.
Austria needs to keep their ally France, though Spain doesn't do much directly to help against Prussia.
Perhaps, previous agreements that Tuscany (her husbands Duchy) will be allowed to remain in the "Main" Habsburg-Lorrain line rather than go to a second son to counterbalance Spain's gain?
Is this feasible?
Charles liked the Neopolitans and was quite popular there.
He didn't want a war with Britan but may have been enticed to maintain the balance of power in America and regain Gibraltar and Minorca.
What would be the impact on Spain's future? Would Naples make a significant difference in the future balance of power?