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 eulogy of the deceased was kind and appropriate.
The deceased was interred at Forest Lawn Cemetary.
The deceased governor was buried in an ornate wooden casket.
The corpse gave no visible clues to the cause of death of the deceased.
his touching eulogy for his deceased friend left all the mourners weeping.
There was great sorrow in the house of the deceased. Parting is such sweet sorrow