Take the fibula bone out of the leg and use it to replace humerus.
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Two bones in lower leg. It can get along.
https://www.microsurgeon.org/fibulaflap
Long time Ortho PA. ABC is a reasonable possibility. Common location and typical appearance. While the bullet fragmented, it wouldn't produce that kind of bony void. Looks like impact was more in the anatomical neck and shattered the glenoid as well. Abduction splint may give better alignment and like most ABCs the trauma may induce more healing. The problem will be the loss of motion and probable fusion of the glenoid with the humerus. Interesting to be able to follow progress, but can see a reverse total joint after initial healing.