Very sad to hear this. He has done some great work, particularly on the Led Zep catalogue with Jimmy Page.
John was regaling me with his story of meeting Mr. Marino while he was remastering KISS's Alive II
for the boxset and even got to hold the master tape box in his hands.
John, you should repost that picture and a picture of Mr. Marino as well if you have one.
Here's one I found: