The ineffectiveness of Radical Constructivism

Have you ever been in an argument with your mother about the way life works and she obviously (hopefully) knows more about it than you do, and she eventually says that single thing that you don't really know anything about, and you are struggling to argue with the fact because you simply cannot refute it based on the fact that you don't know enough. Are a discussion with a doctor in which you say "I've heard this about that medication..." and the response is something along the lines of "Yes,but you need to have this condition and it only happens to a few people." You can't argue with this information because you don't know enough to disprove what has been said;to argue with what has been said. A similar phenomenon comes into play when discussing the theory of Radical Constructivism. Not the details of the discussion,but the outcome of the opponent; he/she is left feeling helpless because the theory is, admittedly by R.C.'s irrefutable. The idea that a Radical Constructivist does not care whether or not he/she is right and is only concerned with whether or not ideas fit with particular individuals makes the theory itself lack 'substance of argument.' (This term is developed by my family and myself). Substance of argument in itself refers to an arguments ability to be seen in more than one scenario and is disproved, or able to be disproved. There is no proof in R.C. just words. No statements are made other than that truth is relative. Radical Constructivism does not get the thinker anywhere in reality. I disagree with R.C. not as a whole, but the problem is R.C.'s don't even care.

Is there an effective argument to a person who does not care about right or wrong?