Did Ian ever even mention a "friend"? He just said he knows a place. It might just be a strategic location that the Empires would "never" look. My guess for how the Ian subplot is continued or resolved:

-Elan asks Julio to rescue Haley's family so the OOTS can focus on saving the world.

or

-The place Ian fled to is the same base mentioned in Panel 6 and he will bump into Sabine who returns there for one reason or another. Then they realize they have a mutual enemy. She won't tell him that she loved Tarquin's son so he doesn't completely distrust her.