Do the paternal uncles and aunt of the questioner's father have the right to object to his father's ownership of the house for which his father paid all installments, and what should his father do about that?

Your father's dutifulness towards his parents and siblings, and assisting them financially while he is in a foreign land, is among the best of deeds. If the money sent by the father to purchase the house was given as a donation and a gift, then the house becomes part of the inheritance and is divided among all heirs, for the Messenger of Allah, peace and blessings be upon him, said: "Whoever wishes that his provision be expanded for him and his lifespan be extended, let him maintain his ties of kinship." However, if the money was sent for them to spend on their needs, and any surplus was to remain his property, then the house belongs to him. And both parties should not forget the grace between them.