Ahmad ibn Muhammad narrated from Ali ibn al-Hakam, from al-Husayn ibn Uthman, from Sama'ah, who said:
I asked Imam عليه السلام about a woman if she died (if she dies and there is no other woman present to wash her). Imam عليه السلام said: "Her husband may insert his hand under her shirt up to the elbows and wash her."
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 1, p. 463