It is not permissible to transport deceased kaafirs to the church, just as it is not permissible to transport their living ones to the church either, because that is helping them in disobedience. The church is the place of falsehood and associating others with Allah, may He be exalted, and if the deceased is taken there, some rituals of kufr will be performed over him that are based on deifying and worshipping ‘Eesa (peace be upon him). Allah, may He be exalted, says (interpretation of the meaning):
“Help you one another in Al‑Birr and At‑Taqwa (virtue, righteousness and piety); but do not help one another in sin and transgression. And fear Allaah. Verily, Allaah is Severe in punishment”
In al-Mudawwanah (4/150) it says: Maalik said: He should not rent or sell his house to someone who will take it as a church, and he should not rent his mount to someone who will ride it to the church. End quote.
With regard to carrying or transporting the kaafir to the graveyard, there is a difference of opinion among the fuqaha’. The Hanafis regard it as permissible to be employed in doing that.
It says in Badaa’i‘ al-Sanaa’i‘ (4/190): It is permissible to be employed to transport the deceased kaafir to the graveyard, because it is a dead body and its harm should be removed from the people like all other impure things.
But it is not permissible, in their view, to transport it from one land to another, because the basic principle is that it is not permissible to transport corpses; rather a concession is granted allowing moving them because it is a case of necessity and it is essential to remove their harm, but it is not essential to move them from one land to another, so the basic principle that it is haraam remains in effect. See: al-Bahr al-Raa’iq, 8/23
The Hanbalis are of the view that it is haraam to carry the bier of a kaafir.
It says in al-Rawd al-Marba‘ ma‘a Haashiyatihi (3/34): It is haraam for a Muslim to wash a kaafir, and to carry him, shroud him or follow his bier, just as it is also haraam to offer the funeral prayer for him, because Allah says (interpretation of the meaning):
“Take not as friends the people who incurred the Wrath of Allaah”
Ibn Qaasim said in his commentary on that: The general meaning of the verse indicates that it is haraam to carry the bier of a kaafir, or to shroud him, or to follow his bier, just as it is also haraam to offer the funeral prayer for him. End quote.
For more information please see the answer to question no. 145532.
It should be noted that there are many ways of earning a living and that if a person gives up something for the sake of Allah, Allah will compensate him with something better than it. So look for permissible work and you will find it, in sha Allah.
May Allah help us and you to do that which He loves and which pleases Him.
And Allah knows best.