My sister's son (20yrs. old) was killed in an auto accident. What is the best type of quilt to make to memorialize such a wonderful boy?

I am sorry for your loss. If he wore cotton shirts, you can make squares out of them assemble them into a quilt.

I am so sorry for your great loss....so sad..... a Tshirt quilt (if he wore alot of Tshirts with logos on the front) is a great idea....or a scrappy one out of his cotton shirts and jeans is another one....the label for something like this is what I always have trouble with....what do you put on a label to express your feelings and yet comfort at the same time? That might be something someone else can help you with too.....I'm not much good with that part.

Here is a link on memory Tshirt quilts

http://www.easyt-shirtquilt.com/
Easy T-Shirt Quilt

You could also take pictures of him and print them onto fabric and incorporate them into some of the blocks. That is so sad. My thoughts are with you and your sister and your families. Losing a child has to be the hardest trial of all!