I'm gonna give you the benefit of the doubt and assume this is not some lame troll attempt(mainly cause it really hit me in the feels).
You are coming across as a real fucking asshole. Don't get me wrong, I'm not saying you are an asshole. That's just what you look like, right now.
She literally said to you....
....she wants to hear his voice one last time. I asked her if she had any video or audio recordings and she said no.
Why would you not, upon finding out you do in fact have audio of his voice, audio of him recounting his life, immediately give it to her? This is a no brainer friend.
A good friend of mine, whom I considered my little brother, passed away. I had video of us fucking around, partying, what-not, and I gave it to his grieving sister and mother and never in my life have I seen someones expression change so drastically or a face light up so much. Those videos helped his family, they helped our friends, they helped me immeasurably.
But even with experience directly related to your girlfriends situation, I can't tell you how it will help or hinder her for you to give her the audio. No one can, except her. I can tell you it's not your place to keep it from her. You're NOT helping her by doing that.
Give it to her and let her decide if she's ready for it or not. Don't be an asshole. :wink: