He's still your son. That's not an obligation you can get out of so neatly.

The best way doesn't make it the only way. Find. Another. At least think about it with a few extra of those angel brain cells. You're smart but you're also seriously dumb if you think you can unilaterally make decisions for the one person in your life that you should be willing to risk even the fate of two worlds for. He should get a say, even and especially if you say he doesn't because you owe him more than that.