We tried something similar with children with SCID [edited] a while back. Many of them were accidentally given leukemia.
Not saying we shouldn't try this, but genetics are capricious, and we should be very careful when trying things like this on humans. Plants and test animals are one thing, but when we're doing trials on humans, there's a lot more at stake.
It involves using cells from his own immune system, known as T cells, after they have been taken out of his body and genetically altered in a lab.
* [1] https://www.npr.org/sections/health-shots/2018/02/21/5853365...