I didn't know what to make of David Gresham being schizophrenic. I have to wonder if Lewis was generally remote at teh time. The longing to see him as a "good guy" might be conjured by Douglas his visible heir, who however is not helping biographers seal the impression of his mother and Lewis being sexual.

https://www.firstthings.com/web-exclusives/2020/09/c-s-lewis-and-his-stepsons