embalmer
A professional who prepares and restores deceased bodies for funerals, similar to an embalmer or mortuary restorative artist.
An embalmer is a professional who restores the deceased's body to preserve their dignity.
納棺師 specifically refers to a person who places the body into the coffin, often as part of a funeral ceremony, while 遺体整復師 focuses on the restorative and preservation work on the body itself.
Compound of 遺体 (itai, 'remains, corpse'), 整復 (seifuku, 'restoration, repair'), and 師 (shi, 'specialist, master'). The term is a modern occupational title.