You only capitalize 'deceased' if it is at the start of a sentence.
My father is deceased.
The movie was played by someone who is currently deceased.
Here are some sentences.He is deceased but his sister is still alive.Is that actor alive or deceased?
The word dead and the word deceased can mean the same thing and so they are synonyms.
The pathologist performed an autopsy on the deceased.
The deceased was interred at Forest Lawn Cemetary.
The eulogy of the deceased was kind and appropriate.
The corpse gave no visible clues to the cause of death of the deceased.
The deceased governor was buried in an ornate wooden casket.
A requiem is a funeral mass. An example of it used in a sentence is: After the viewing, they held a requiem in the church for the recently deceased gentleman.
his touching eulogy for his deceased friend left all the mourners weeping.