My father is 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.
You only capitalize 'deceased' if it is at the start of a sentence.
I would think the root word is "Cease." Like in the sentence "Cease to exist." I may be wrong, though.
There was great sorrow in the house of the deceased. Parting is such sweet sorrow
his touching eulogy for his deceased friend left all the mourners weeping.
We attended the wake for the deceased last Monday evening.
The recently deceased knight had bravely faced the enormous dragon.
Doug gave the eulogy at his father's funeral. (Eulogy being the speech in praise of the deceased).