There is no evidence to suggest that Albert Einstein was angry during the last days of his life specifically because he was unable to prove that there is no God or that the universe was created by natural processes. It's important to note that Einstein's views on religion and the existence of God were complex and evolved throughout his life.
Einstein described himself as an agnostic, which means he believed that the existence of God or a higher power is unknown or unknowable. He did not adhere to traditional religious beliefs, but he also did not consider himself an atheist. Einstein often expressed a deep sense of wonder and awe for the natural world and its laws, which he sought to understand through scientific inquiry.
While Einstein did engage in philosophical and scientific discussions regarding the nature of the universe, it's not accurate to claim that he was solely motivated by a desire to disprove the existence of God. His scientific pursuits were driven by a curiosity about the fundamental workings of the universe and a desire to uncover its underlying principles.
In his later years, Einstein focused on his unified field theory, an ambitious attempt to formulate a single theory that could explain all the fundamental forces of nature. However, he was not able to achieve this goal before his passing in 1955. Nonetheless, it is not accurate to attribute any specific emotional state or frustration about the existence of God as the primary reason for his pursuits or his feelings during his last days.
It's important to approach historical figures with accuracy and avoid projecting personal beliefs or assumptions onto them.