A little background: My brother, dad, grandfather & late great grandfather all have the same first, middle and of course, last name. It is a pretty rare first and middle name and I don't want to use actual names so in this case I'll use Rodger Alexander (first and middle name actually start with R & A, this is important). I'm a FTM, this is also my partner's first and we just found out we're having a boy! All the excitement aside, I've been dead set on Wallace 'Alexander' as a name for a boy and never even picked a name for a girl. This has significant meaning to me bc Wallace (actual name) is my late grandfather's middle name (mom's side) and 'Alexander' is my grandfather's and dad's middle name. It's worth mentioning that my partner's last name starts with an R so his initials would be WAR which we think is really cool. My partner's initials are HAR and I wanted to have a running theme of everyone's last 2 initials being AR. Well when I announced to my immediate family that my partner and I were expecting, I received "congratulations" and "how are you feeling" from everyone except my brother... He instead, texted my sister and I separately staking claim on my grandmother's first name as a middle name for his future daughter. Keep in mind he is not dating, married, etc. When he texted us this I told him I had no intention of naming my child that and instead told him my name ideas. I said for a girl I want to use the middle name Ann (mom & grandma's middle names) or Louise (sister's middle name). If it were a boy, I wanted to name him Wallace 'Alexander' after our grandfather's (we didn't know gender yet). Well, this is where things took a turn and in hindsight I should've just kept my mouth shut. He lost his actual marbles saying things like "That’s not fair to me", "If you love me at all, you won’t use that name", "Also my name and you’re messing with my ability to name my son", "So I’m just gonna have to explain to my son that oh yeah but that middle name that’s been sacred to 'Rodger’s’ ever since this family took the name on oh yeah your aunt decided she could do whatever she wanted with it", "All I’m asking for is the respect I’m owed. If the roles were flipped I’d be mortified if the thought of stealing the name even crossed my mind". I pushed back a little and then dropped it bc we didn't know what we were having yet. Also, he is known for his dramatics and taking it out on others when things aren't going his way. I think he's a little upset that his younger sister is getting married and having a baby before him and also a lot of his friends are getting married/engaged which can't be fun. Now that we do know, I am really set on naming him Wallace 'Alexander'. After talking to some friends & family members they all, with the exception of my mom, agree that he is overreacting. My dad said he loves the name and I even asked him if his siblings had done something like this would he have been upset to which he said no. I'm telling my grandparents on Friday and will get their opinion also. However, I trust my mom more than anyone and just want to know AITAH for wanting to name my son this?

EDIT: It's worth mentioning that he does plan on naming his son (if he has one) after himself to keep the family tradition going. So there with be a 5th 'Rodger Alexander [last name]' not sure if this affects your verdict.