Sorry your bio sister and egg donor are horrible people. You have no obligation to deal with them and have the right to live a peaceful life. Don't let your father guilt you into interacting with them. He may wish to speak with his other daughter, you need to watch our for his interests.
If he wants to speak with sister make it clear that it will happen in a well lit public place like a cafe for a specific amount of time, and you will drive him to and from the place. Take him there and sit a discrete distance away so you can keep an eye on them. Most likely she will give him some sob story and want money, once seeing he has very little will try to guilt him into giving his last penny or taking out loans for her.
Talk to a lawyer or doctor about becoming his financial Power of Attorney, since he's getting older and wants to reconcile, he's an easy mark. Email you landlord and tell him a scam artist claiming to be your sister is trying to scam your elderly father, this way if/when she arrives at your door you have a paper trail with the landlord and call the police. Do this calmly, she'll count on you not wanting her to make a scene and upsetting your neighbors.
Hope this helps you and that she goes away when she she's there's no more withdrawals available at the Bank of Dad.