He has quite bad hayfever and I recommended he eat local honey. My parents gave him a jar of honey from their road (35 miles away). I have since read more and believe there is no benefit. Fine, except DH is convinced it's working and is very happy eating honey regularly now. He appears to be experiencing a placebo effect. I have therefore said nothing about my further reading on the subject and am allowing him to continue benefitting from the placebo. AIBU to conceal the truth in order for the placebo to continue working?