thanks! A minor improvement would be to put tree-ish at the end;

    log --graph --pretty=format:'%Cred%h%Creset - %s %Cgreen(%cr) %C(bold blue)<%an>%Creset %C(yellow)%d%Creset' --abbrev-commit --

Be honest. Tell them about your thoughts and conclusion (that this is not sustainable), there is a fair chance this will resolve your predicament _and_ strengthen your relationship.