The ultimate question regarding the "necessary and proper" clause is not whether it empowers the Congress to regulate this or that, or prohibit one action and require another. Such questions inevitably devolve into academic parsing of words, attempts to divine context from Benjamin Franklin's personal habits, and a litany of examples attempting to prove the disputed points by deduction. In fact, the courts of this country have considered virtually innumerable cases regarding Consitutional interpretation, each involving contesting parties with more or less valid arguments. The observation that the rules of such cases are occasionally overturned and superceded are evidence that there may not be a right answer; the Supreme Court after all delivers its judgments as opinions.
True conservative are correct to defend principled interpretations of the Constitution; however, as the country approaches the event horizon of a fiscal black hole, the focus shifts appropriately from theory to practice. The practical issue is not whether Congress may enact laws codifying altruism (although this is certainly a valid inquiry), the real issue is whether the Constitution enables Congress to do things like regulate the speed of light or eliminate asthma through appropriate legislation. It really doesn't matter if the Constitution allows Congress to legislate away at a problem if the problem is not solvable by legislation.
The framers of the Constitution were much smarter than the mass of legislators that followed them. They realized that there were certain habits and principles that separated those societies that would prosper, and those that would devolve into tyrannical failures. The founders knew that programs that depended on the coercive power of the state would ultimately fail. Unfortunately, part of the appeal of government solutions to problems is that the government can use force to compel compliance, and has what is regarded as an unlimited credit line. These create the mistaken illusion that the government can solve everyone's problems without creating more if its own.
The founders realistic view of how societies progress is not found in "evolving" interpretations of the general welfare clause that authorize the domestic use of force in pursuit of fashionable and photogenic causes. The pragmatism of those serious men is found in Article 1 section 8(8) which allows Congress to "To promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries." Imagine for a moment the effect if this instead allowed Congress to "compel authors and inventors to develop the useful arts to promote the general welfare," or to "appropriate for public purposes those writings and inventions which shall be found useful." How much promotion of science and the useful arts would have happened? The founders wisely resisted the compulsion to compel; their descendants sadly have not.
The patent clause also contains something of the general welfare spirit that liberals claim is lacking in libertarians and conservatives: it limits the duration of patent and copyright protection, thus implying that, after the inventors and writers have appropriately benefitted from their efforts, the general public should be allowed to expand on them and put them to useful purposes.
Medicare may have been a reasonable idea when it was still an abstration in the minds of sentimental, if short-sighted people. It may in fact have some role in an advanced society, but the more it is larded up with regulations, rules, penalties, mandates, and other devices irritating to the ideals of a free society, the more it is destined to fail, and cause a lot of misery in the process.