Two versions?
He got sent to the 2050's because he's over 40 and dead long before then
But His daughter knew to send for him on this day because how?
There was no tomorrow war in her past, she would have never known the exact date he arrived, and that he survives his 7 days and went back
Making her plan only make sense if its random and based on faith that one day her dad is gonna come thru that portal with other draftees and then help with her plan.
Two timelines:
Timeline A - He comes back and due to there being no solution to prevent/defeat the aliens, he spirals out like his father. This gives the daughter the motivation of being better than him and becoming the leader of the future force.
Timeline B - His daughter of timeline A knows of his draft schedule and that he survives, so she brings him to be the courier for the toxin. He comes back with the solution, prevents the war, saves his family and creates a new timeline without the aliens.
Timeline A - He comes back and due to there being no solution to prevent/defeat the aliens, he spirals out like his father. This gives the daughter the motivation of being better than him and becoming the leader of the future force.
Timeline B - His daughter of timeline A knows of his draft schedule and that he survives, so she brings him to be the courier for the toxin. He comes back with the solution, prevents the war, saves his family and creates a new timeline without the aliens.