Making Dua for one that donates Haraam wealth

The Mas’ala in question is recorded in Fataawa Hindiyyah in detail. Fataawa Hindiyya states that if a person gives charity with funds (acquired from Haraam wealth) to a poor person with the hope of attaining reward then the giver/donor becomes Kaafir.

And, if the poor person was aware of it (being Haraam) but made Dua for the donor, and the donor in return said Ameen to the Dua, then both (the donor and the recipient) lose their Imaan.

In conclusion, the Mas’ala recorded in Kitaab-ul-Imaan refers to the latter case where both parties lose their Imaan. (Allah forbid!)