Answered once and re-answering because I hate adding extra context in replies that people might not read

First of all thank you! I passed out like a rock lmao

Second of all, and yes I am exactly this kind of pedant, the lines are:
"... 一番の財産は武雷管の修羅、辰宮 晴臣。お前だよ。> (EXTREMELY LITERAL) "His greatest asset was Buraikan's Shura, Shingu Haruomi. That's you."

So when the very next line is "命をかけて守ってくれた", I think it's safe to assume that since he's extremely explicitly describing Haruomi in sentence A, he's probably talking about Haruomi in sentence B. This is of course setting aside the fact that we already know that Haruomi risked his life to try and save Chisei, because Haruomi attempted the first metal kiss mind dive (see: VIBES drama pt.2-- though note that AFAIK this is actually the first time Buraikan have brought it up directly themselves!).
Then Chisei later says that he's the one who benefited from the inheritance more than Haruomi himself > he benefitted from Haruomi.

The reason there might be confusion is just because Japanese omits subjects a lot, so the literal sentence "命をかけて守ってくれた" LITERALLY just translates to "risked their life to protect [me, implied by the ~kureta]", with no explicit indication of who was doing it.

So if you assume he's still talking about Haruomi's father, that may be the source of the confusion; but the way I read it, the segue between "お前だ" and "命をかけて守ってくれた" basically reads as "you, [who] risked [your] life to protect [me]", especially with the later context of him saying that he's the one who benefited from the inheritance.

But I'm not making that assumption, again, because of later lines in the drama and the fact that we already know that Haruomi has done stupid things to try and save Chisei.