The first thing that we know about Grandpa is that he snorts heroin. He doesn't think that his kids or grandkids should snort heroin, but it is OK that he does because "he is old." In a moral universe defined by 'situational ethics', old age creates a situation in which there are no consequences for what would be unwise behavior among younger people. Older people are going to die anyway, so nothing can have a worse effect, so, therefore, everything is allowed. When it comes to sexual behavior, it is the same. His advice to the young men in the family is to have as much sex as possible with as many women as possible. Approaching the end of life, Grandpa is a distillation of the "please yourself" ethic of the baby booming generation. The "triumph of the will."
Do I think that this is the way that my age cohort really is? Not really, but that is not the point. The point is that is what the generations that follow us have concluded to be our operative ethics.
Richard, the direct son of Grandpa, has understood how culturally appropriate this ethic is in this society. He has tried to commercialize the willfulness that he has inherited as a self-help program which tries to teach people to be "winners" and "the put the habits of losers behind them." One of the strands of the plot is that this effort fails, despite his heroic and repeated reinvestment in the idea that losing is only in the mind.
It soons become clear that Grandpa is really just so much dead weight and baggage that must be carried by the generation that follows.
The end of the movie is quite touching. In the end, this family unites and pulls together to protect Olive from complete humiliation which had been created by Grandpa. In the end, loyalty to family is the supreme value.
This is not just a sentimental, feel-good, life-affirming happy ending for a movie. It is a stone-cold, razor-sharp and completely unmerciful statement of generational antogonism. The children of the baby-boomers, the children who have grown up in the most broken homes as any generation in history, say that loyalty to family is the most important value. It is stunning declaration of what they feel that they have been denied, what they never received.
Not since "Four Weddings and A Funeral" has a light comedy carried such an insightful and angry punch to our collective solar plexus