He knows the future. He knows that real money/power comecomes from technology. He needs technology for the future invasion.
So... educatehe educates the mob's children. Send them to college/university. Have them study in economics, chemistry, physics, law. Have them become doctors and engineers. After graduation, establish companies, research centers, law firms, shipping companies etc
Buyout all, to create the first mega-corportaioncorporation, a multi-billion international one. Invest
Invest in researching new drugs, new weapons, what everwhatever you will need to fight the aliens.
The old Mafia will continue its traditional methods, until the fathers die. The new Mafia (their children) will become "modernized" - electronic espionage, hackers, R&D of high tech, drug testing, ... whatever you want/need.