QUES: During the afternoon he received a visit from Crister Stark who had come to check his progress

correct the punctuation.

CORRECTED: During the afternoon, he received a visit from Crister Stark, who had come to check his progress.

QUES: Everyone knows that he must die and death plays in ones life maybe the most important role

correct the punctuation.

CORRECTED: Everyone knows, that he must die and death plays in one's life [maybe] the most important role.

QUES: His stay in Paris is described in detail in a diary he kept

correct the punctuation.

CORRECTED:
His stay in Paris is described in detail in a diary he kept.