Because He loves Iris, remember the frog scene where Ian fell for Iris the first time and when his father The Emperor died, it was Iris who stood by him and cheer him up (it all happened before Iris reincarnated since she reincarnated at 20, but Iris doesn't remember her childhood memories), so Ian love for Iris has nothing to do with her reincarnation or how she suddenly became smart and strong.
But just like you said the past Iris was weak willed and pushover and so Ian said this to Annakin before 'all he can do was watching her from a far, he can only step in if there is a real danger, there is no way for him to tell Iris that she was being manipulated by her fiancee and so called family', that's why when Iris came to information hall, Ian offered himself but Iris didn't even trust him. The past Iris loved Howard and trusted Nera, that's the reason why Ian choose to leave Loenheim instead, he thought Iris would be happy with Howard but when he returns 10 years later Iris was accused of treason, he tried to save her from the Prison but after being on the run for a while, Iris was caught and shot by Howard, hence why he gave up his life.
I didn't say his love had do to with anything lol
Well except her being reincarnated
I just said that what Ian demonstrated was an act of true love since he had no idea if she really would be happy in her second life
Wooooow
Ok
But why the F does he not remember the dream! So annoying
He must have had a lot of fate in Iris if he chose to give up his life for something so uncertain
For all he knows she could have stayed weak willed and be a pushover all over again
I'm glad she's not
Iris is dope