real or not?

how goes it guys. NFL season just around the corner. Question, maybe some of you can help.
I am about to buy a autographed Marino Jersey for my brother. But the guy ( although seems perfectly safe ) say's he lost he COA and only has the hologram on the jersey as authenticity.

thoughts?

Welcome, it will depend on which company is guaranteeing the signature. If its one of the good ones like JSA then you should be ok if it's not a well known company then personally I would steer clear. The COA will only relate to the signature, these players will sign anything so it's no guarantee that the jersey is a genuine jersey, in fact 99% of signed jerseys are counterfeit and you have to be real careful about the autographs too as most are fakes too.