I am excited to see how many points I am eligible for.

If you haven't signed up yet, you'll need to sign up for the rewards program at
http://rewards.xbox.com to start earning credits. All offers to receive credits are listed on the Missions page of the site.

If you are already signed up, you can see how many credits you have earned on the MyRewards section of the site. Credits are deposited into your Microsoft account balance by the following 15th or 30th of the month after you have at least 5,000 credits pending,
or you can request a deposit once you have at least 1,000 pending.

I loved seeing how many games would be on GamePass the day they launch. I am particularly excited for Minecraft Dungeons though!

If you mean the currency expired and you didn't use it, you could try contacting support and speak to billing to see if there is anything they can do, but generally once funds have expired there is no way to get them back. Http://support.xbox.com/contact-us

There is no way to prove it was your brother or you who purchased it. If you were to get a refund that would open the door for millions of "it was someone else" claims.

You could try calling or chatting with someone from xbox support just to check, its always worth talking to a person. If you have had a refund recently it could affect this one though. As well as the fact that xbox states all sales are final, so returns
are not a sure thing. While it may meet the criteria for a return I do know you cant just return a game simply because you do not like it. That being said if you selected that you did not purchase the game in the return request I would highly suggest calling
and seeing what they can do.