How do I get my 42 yr old brother to move out?

I let my brother move in with me and my 3 children in October last year. He said he would save for a place and be out in the spring. I have an in-law suite connected in the back of my house and he stays there. I do not charge him rent but he helps out by fixing things around the house and buys some of the groceries. I have recently found a 1br/1ba house for rent that he can afford. He was excited about it and was going to rent it. He has now started saying he should wait because he has nothing of his own to put in the house. I told him to make a list and our mom and I would get everything he needs. When he moves out my boyfriend of 2 years was going to move in. My bf and I were so excited that we were finally moving forward with our relationship. My brother, now has put a damper on that by stalling. I believe he is stalling because he has never lived by himself. He's the only family I'm close to and don't want to cause a rift between us but he really needs to grow up. I was on my own at 18 and my 20 year old son is on his own. Any advice would be great. I am not going to just tell him to get out or be rude to him.