The real estate license is my name. Father lives with his grandson's son and daughter-in-law Zhu, and now he doesn't want them to live. What should I do?

Then tell them a reason. You use this house and let them go out to find a house to live in, but you have to give them time. Did you buy the house in your name? Does your father have his own house? There are other reasons. You didn't buy it yourself, nor did your father pay for it. You just wrote your name, so you should go through legal procedures for your reference.