Unfortunately, house fires differ from cigarette smoke or mildew smell in that intense heat is involved. The heat, I believe, interacts with the fabric, causing the smell to be more absorbed.
My parents had a house fire and had to replace most textiles. However, they used a combo of mild and white paint when they repainted the basement; crazy idea but I wonder if either straight milk or a milk based solution might help (after you do a test with a small piece). Also, try soaking the fabric in a vinegar solution (a less crazy suggestion).
Best of luck to your friend.