If you want to keep the birthday a small kid/family celebration....ok, I wouldn't just ignore it. However, if he is really having a hard time turning 40 and he is telling you with no joking aside that he doesn't want a "party".....then I would heed the warning b/c I think that is just what it is.....a warning.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!