What would be a critical thesis statement for Winter Dreams?

I think that much of this question would be dependent on
what you were able to take from the work.  I think that you have to go back to the text
and identify what elements were the most prominent in your mind.  For example, what
statements or observations can you make about the relationship between Judy and Dexter? 
What does this show?  What might this reflect about society?  At the same time, what do
you take away about Dexter?  At the end, when Dexter talks about "That thing will come
back no more," to what do you think he is referring?  These are merely starting points. 
In the end, a thesis statement is best conceived, analyzed, and addressed when the
writer finds something to which there is connection and
resonance.