I gave my brother my Xbox one as I had 2. Can he keep my gamertag on there and play my digital games? I know they follow my gamertag and not the console. Will this work?

Yes, he should be able to. I bought one used on Ebay last summer and up until 2 months ago I was able to play the digital games that were on the system as the seller kept his gt on there. Only reason I could think the 2 games no longer work is they perhaps did not renew their membership.

I found out if I make this new one the "home xbox" he can't play it. So I just deleted all the gt's but mine as well as all my credit card info. Put a password on it as well and he can't get into my account. Lol

Just FYI, we already have a thread for Xbox One and all related issues. You don't need to start a new thread every time you have a question about it.