Question:

What do the pious and expert scholars of Islam say: Is it allowed to cut the hair of the deceased after death?

Answer:

It is not allowed to cut the hair and nails, or to comb the hair after death. It is Makruh Tahrimi (offensive). (Durr al-Mukhtar)

And Allah ﷻ knows best

Shaykh Hassan Rabbani Al-Azhari