if only the coaching staff will give him enough playing time, he can give more help the team to win.
It won't happen. Instead of giving him enough playing time, why not give that playing time instead to a caliber player?
He's fit in the supporting role, not as a part of the main cast. He can be a valuable backup.
Anothe reason why he is given limited playing time is, it was the health recommendation after being in a major injury.
I agree with you, otherwise, cousins would not be having a hard time getting signed into a team. The fact that he only gets a short-term contract, that only means that the team sees the risk that he could be injured anytime and he will be a liability again to the team. Being in the 2nd unit is more effective for him, and getting limited minutes would help him minimize the risk of getting injured.