What, in the end, frees Wilhelm?
Wilhelm, throughout the book, longs for freedom. He does not know it when the book begins but, on the day in which the book's narrative action occurs, he will achieve such "freedom."
To answer this question one must answer what it means to be free, at least within the context of the novel. Tamkin claims, in Chapter IV, that man is tied down by social control, egotism, vanity, and most importantly by the conflict between the "pretender soul" and the true soul. The "pretender soul," continues Tamkin, is attached to social control. Moreover, although Tamkin's language is mocked in many ways, Tamkin is nevertheless expressing some kind of truth. To use Tamkin's words, to be free, Tommy must free himself of his mask, allow his true soul to replace the "pretender."
Furthermore, to do this, Wilhelm must stop playing the "roles" he has been holed into and he must find the person that he really is. For instance, throughout the book, he is seen, and sees himself, as "Dr. Adler's son." Dr. Adler needs to abandon him for him to unlatch himself from his role as his father's son. Later, Tommy becomes attached to Tamkin and the same disatachment is necessary. He needs also to release himself from money's grip and so he must lose all of his money to unhinge its leash. Further still, he needs to release himself from Margaret, not from his obligations as a father, but from his victimization of her. In short, the paradox lies in the fact that one must lose everything in order to be free.
The other and final element that frees Tommy is that of love. Once Tommy knows who he is than he can find solidarity with the rest of society and become part of the "larger body" of humanity, instead of always being isolated in the crowd. In the end Tommy feels love for the people around him, as in Times Square, and he feels love for the stranger in the coffin. It is a beautiful irony that the self-same society that constricted him can, in the end, be a freeing force also.
What is Wilhelm's basic struggle?
Seize the Day is filled with psychological jargon and, therefore, in following with the book's form, one can say that the book, in Jungian terms is an enantiodrama. The term means simply the process of being torn in many directions by "pairs of opposites." This term applies to Wilhelm's basic struggle because his basic struggle is internal. Or, rather, it is that of his internal self combating the external world, since the internal and external worlds are opposites.
To say that Tommy's struggle consists of the internal vs. the external, however, is too vague. To be more specific we must highlight some of these struggles. For instance, some of the opposing forces at work that create a struggle in Wilhelm are the choices posed to him by his father and his father's way of thinking vs. those "alternative" choices posed by Dr. Tamkin, his surrogate father. Tommy is struggling with the demands of the world around him. However, his problems seem amplified and larger than most peoples because he is not aware of who he is and so the problems of his everyday life lie heavy upon him.
There are many ways to address this question, however, the most important factor in discussing its answer, is to realize that Tommy's struggle is internal and that this "internal" struggle is, in many ways a modern one. This is not to say that the human being has not been struggling with the sense of self for all of time. However, the discussion of such a topic allows for a new way of writing, a way of writing that has become known as Modernism.
What is Dr. Tamkin's role in the novel?
Dr. Tamkin takes on many roles throughout the novel: the role of surrogate father, the role of "truth-sayer," the role of leading Tommy, and the role of healer/psychiatrist. Tamkin claims to occupy many positions in society from master builder to inventor to psychologist and although he seems to lie or at least exaggerate, many of his roles are fulfilled.
Tamkin, many times, appears to be a liar in his claims, but there are many a truth hidden within the lines of his "lies." Tamkin claims to by a psychologist and, in fact, in the end, proves to be healing Tommy. Tamkin presents Tommy with alternatives and with many ways of thinking which open a new kind of path for Tommy that, in the end, lead to self-healing. Furthermore, by the very act of offering his assistance, psychologically and emotionally as well as monetarily, Tamkin is acting as a father should act. Moreover, he becomes a father figure for Tommy, a surrogate.
Finally, it is important to understand that although Bellow may use Tamkin as a source of parody, he also uses him as a source of truth. This makes perfect sense because Bellow is fond of paradox and he is also fond of the wavering lines, rather than the straight paths, that lead a person to understanding.