I think my dad spies on me with my computer

So a few years ago he gave me his old computer, I made it my own by putting a password on it and I even made a Guest account just in case he needed to use it.

Well, today, I went to use his MacBook and I found something called Remote Desktop Connection, which is basically a program that you use so you can connect to a Windows computer from anywhere. Now, I'm worried he uses that to connect to mine, but how do I know if he can use it to connect to my computer? I've always been paranoid if this happening my computer for some reason isn't working properly, so how can I ask my dad about that program without making it sound like I'm hiding something? In a way, I am hiding something. But it's not necisarely bad, it's basically just pics of me without a shirt (for my workout program I did a while back) and it has a few embarrassing Microsoft word pages that contain nerdy little books I made up.

Edit:

So I talked to him about it and I said "What's your password for the RDC?" And he acted like he didn't know what I was talking about and I said it ca access my computer wirelessly from his and I need to use it, and he still said "Oh I didn't know you could do that" he claims he would never search my computer or anything. But idk if I can believe him.

Click the windows icon and rightclick computer or rightclick the computer icon on your desktop and select system properties. Look for remote settings tab and click it. Make sure allow isn't checked.