So sorry about your lost. Making the t-shirt quilt I hope will help in the healing process. I recently made a memory quilt with my niece's mother's clothing. she died from lung cancer. It was a challenge but similar to a t-shirt quilt. You have to back the tshirt piece that you use with stablizer. I have also made 2 t-shirt quilts. cut the front of the t-shirt as large as you can. When I did mine I cut the front as a 12-1/2" square and tried to use all of the "logo". Smaller ones, I made 4-1/2' squares and put 4 of those together to make up the finished 12-1/2" block.
I sewed sashing around the blocks. I had them hand-quilted by an amish women and they came out great. sending along a pic of the menory quilt which is similar and hope it helps. thoughts and prayers are for you.