Dr. Ambrose cites the 99th Infantry Division at least nine times, and the 395th Infantry Regiment five times in his remarkable narrative of operations starting with D-Day, to the Battle of the Bulge and finally the German surrender.
The pages devoted to 395IR all center on the Bulge, and he is so expressive that you will feel the stressful action as well as the weather conditions.
Unfortunately, I couldn't find reference to "I" Company, but there are at least two made to Charlie Company.
I would assume that whatever happened to "C" would apply to "I" as well.
I sure hope that this is of benefit to you and your family.