Your father remains your father, he gave
birth to you and saw you through school and life. No matter his down side, give him the best he deserves and you will be mightily blessed.
I suggest you buy a small piece of land at the outskirts of the town and build a three bedroom bungalow for him in your name and when he passes on the property reverts to you. Perhaps the reason why he sold his other house in the city is because of the attitude of your siblings, but you love him, then go ahead and show him more love.