You or your brother could transfer points to the other. You are allowed one in or out per UY.
The points dont ever change resort or their UY and have to be used within those rules,
So, even transferred, your SSR points remain good only at SSR until 7 months out and his AKV are only good at AKV until 7 month out, regardless of the account they move to.
Once transferred, the points can be banked, but not borrowed, Since you have different UYs, you’d need to think about which ones should go to be sure they are good for the trip, as that is what matters.
For example, say you wanted to travel in July 2023. It is in your June 2023 UY but his 2022 UY.
To combine points, you’d either need to transfer your 2023 points to him to be used with his 2022 points, or he needs to transfer 2022 points to you to be used with your 2023 points.
You would not want his 2023 points transferred to you because they would not be eligible for the July 2023 trips as they cant be borrowed once he gives them to you.
To do it, both of you have to call MS and be on the line.