Does the Friday prayer become void for the washer of the dead if its time repeatedly clashes with washing the deceased at specific times that cannot be delayed?

There is no objection to working for this company. If you are required to be present on Friday, make sure to perform the prayer. The company does not have the right to prevent you from it, and you are not permitted to abandon it for this reason unless you fear harm or corruption affecting the deceased from delaying the washing, or you fear harm to your work, which you need for your expenses and the expenses of those you support.