Some synonyms for “as he is aware of” could be “since he knows”, “because he is cognizant of”, or “given that he is conscious of”.
“Since he knows” implies that his knowledge is the reason for a certain action or understanding. For example, “Since he knows the area well, he can guide us through the city.” This shows that his knowledge is a factor in a particular situation.
“Because he is cognizant of” uses a more formal tone. “Cognizant” means having knowledge or being aware. For instance, “Because he is cognizant of the risks involved, he takes precautions.” This indicates that his awareness leads to a specific behavior.
“Given that he is conscious of” also has a more formal or academic feel. “Conscious of” means being aware or having an understanding. For example, “Given that he is conscious of the importance of the issue, he devotes time to address it.” This shows that his awareness influences his actions or decisions.