Stepdad or Uncle?

[nx1701g]

SPOILERS

During the phone call during the car chase who is Kirk talking too? I've heard people say its the Uncle, but Greg Grunberg is credited as Kirk's Stepdad.

Which is it?

 

[Brent]

I guess they never state it directly on screen do they?

 

[Venardhi]

I assumed step-dad.