What does your friend think he will achieve by bringing it local -- what is the goal?
Having lot of "technical debt" sound like that the implementation is broken as it is, and moving the development from one team to a next team would not real this -- but rather as other have indicated, in the short term make it worse, as new people unfamiliar with the code have to struggle with a mess left behind by others.
Aqui-hire or not is not the question. The question is whether your friend have confidence in the current code base (does he even have any real knowledge on the code?) -- and if not would he be willing to take drastic action ? How to get the right team should be a question to answer once the situation is understood and a plan is made.
I help companies on a CTO-for-rent basis -- If interested, drop me a mail.