We went on a date. On the date he kept complimenting my appearance, making me laugh, and treated me kindly. He texted the morning after and said he had fun and I was great company. Days after he suggested we hangout again and that he wouldn't mind being a thirdwheel. Does that mean he wouldn't mind being a thirdwheel to me and another guy? He said I could bring a friend. When I asked who, he said my sister. My sister is someone he's shown interest in before.