The remake (#G09) has this trait:

COORDINATED ASSAULT: Once per turn, when another friendly character with the Robot keyword hits an opposing character, Sentinel Mark V may make a close or ranged combat attack against the hit character as a free action after actions resolve.

As far as i can tell as it isn't specified this means that he can do it regardless of line of sight or range or being adjacent to them or other characters.. is this correct?

no he is making either a ranged or close combat attack, which follows all the rules associated with each type of attack.
So he would need LoF and range.

No, it would have to specify that he can break the normal rules for range or line of fire in order to do so. Without anything specifically stating otherwise, the normal rules will be followed.