Did you miss the part where it says "He shall see his seed [children], he shall prolong his days"? No-one is being physically sacrificed here. All that's being said here is that HaShem desired to make the people sick so that they would turn to Him again and repent. Here is the verse from a Jewish translation:Wrong!
10 Yet it pleased Jehovah to bruise him; he hath put him to grief: when thou shalt make his soul an offering for sin, he shall see his seed, he shall prolong his days, and the pleasure of Jehovah shall prosper in his hand. 11 He shall see of the travail of his soul, and shall be satisfied: by the knowledge of himself shall my righteous servant justify many; and he shall bear their iniquities. 12 Therefore will I divide him a portion with the great, and he shall divide the spoil with the strong; because he poured out his soul unto death, and was numbered with the transgressors: yet he bare the sin of many, and made intercession for the transgressors.
And the L-rd wished to crush him, He made him ill; if his soul makes itself restitution, he shall see children, he shall prolong his days, and G-d's purpose shall prosper in his hand.
The soul needs to repent for all it's done. This is about Israel's transgressions and Israel interceding on behalf of transgressing nations. Israel needs to repent.
Also, if, as you believe, this referred to messiah, the messiah is clearly alive a while and has children and will prosper. Not your man.