Question

With God’s help,
Hello Rabbi,
After the Passover Seder night, a cousin who is a mechanic wanted me to give him some moral instruction, and although that’s not really my genre, we opened Duties of the Heart. There, at the opening of the Gate of the Service of God, he explains that if a person benefits someone else without intention, then there is no need to thank him, and then he lays out a list of examples and in all of them concludes that the main motive is egoistic. Yet even so, the Torah (and perhaps reason) obligates people to thank them. Starting with a father toward his son, and including the compassion one person shows another poor person, where he does it only in order to get rid of the feeling bothering him.
After that we closed the book.
But we were left with the question: is there really no concept of altruism in Duties of the Heart? Is that it? Is every human being doomed to egoism?