Many years ago, Gail Binney-Winslow had a traveling exibit of the quilts featured in the book "homage to Amanda". She is an heiress to the Crayola Crayon fortune and she and her father collected over 300 quilts, which went on tour to promote her book. I was lucky enough to have a guided tour of the exhibit, hosted by Gail herself and at the time, she spoke of the "mourning quilts" she was working on. Within a year she had lost her father and I believe her husband. Very huge losses in her life. Whenever she missed them or felt overwhelmed with sadness, she would work on a quilt in their honor. She had 2 separate quilts going and they were awesome. Applique. I thought it was a great idea. It turns times of depression and sadness into something more productive, which I think is a good thing. It can turn depression over your loss into more positive thoughts, looking at the good times you shared. It doesn't sound as if you have fabrics which are really cohesive enough to use in one project, but it may be nice to try using some of the cottons from your brother's shirts and use them to frame some pictures you may have of special memories and incorporate them into a postcard quilt. Collages of some of his things in a shadow box is a nice remembrance, and you can make some for other family members. Teddy bears with cloths made from his sweatshirts or pillows made from them are comforting. Give it some thought and i am sure you will find many ways to use his things and to have comfort from them while you do so. It's a way of keeping him with you, which is much better than keeping his things in a bag, IMO.
Best of luck to you!