These tests have had little oversight with little research backing them up. For some medications, the evidence is strong. Note how the company hedges on their site: "Gain Insight on How Genetics
May Impact Medications."
Also, note that the test is about drug efficacy at a biological level,
not whether a drug is properly indicated for a person. In other words, I can take the test today and get information on whether a statin would work for my body, but it doesn't mean that I need to take a statin (I don't).
@Outdated is correct in saying that the test could be about the "can" take the medication, but not the should.
@salempeacock Please talk to doctors who have examined your grandson and have considered the risks and benefits.
More info on the validity of the tests:
https://psychnews.psychiatryonline.org/doi/full/10.1176/appi.pn.2018.pp6b1