Sorry for your loss.
My idea for this is to use plaster. I actually found for $10.00 at Walmart, in the craft section, a kit to mold plaster. This is directed for children and the shapes were hearts. It was easy to mix and pour into the mold. It had a nice design on one side that I let the kids paint when it was dry, but on the other side I smoothed the surface and put my kids hand in it to make a print.
We gave these to grandma for her garden though she mounted them in her living room.
Here's a link to the product we bought for an idea of the concept.
You can probably find plaster/mixes at craft stores and make your mold. This would be inexpensive and you can carve and customize it.