Mark Kerrigan is charged with manslaughter in the 2010 death of his 70-year-old father.
Prosecutors say Daniel Kerrigan died after a fight with his son. Kerrigan's lawyer and family say Daniel Kerrigan had a heart condition and his son was not responsible for his death.
Kerrigan's lawyers argue in a motion to be heard Thursday that he did not voluntarily waive his right to remain silent due to "severe intoxication."
Police have said Kerrigan told them he grabbed his father by the throat and pushed him, and then his father slumped to the floor.