Well, yes it does matter, because who else has the right to make such a decision? Well, yes, it could have been any of those family members, or someone who had no authority to do such a thing.
Been there, had to do it for my husband. It is not a decision that the doctors let you make lightly, and hospitals are very strict as to who they let make the final decision. Our sons had no standing with the hospital, it was all on my shoulders. Of course we all made the decision together, and they knew I just couldn’t do the physical part. Our darling boys removed that chunk of guilt before I could even put it on my shoulders. Very hard, very brave.