Let him come back if he wants to.
If he does, he'll be the most heavily watched Canadian since Pam Anderson was in her prime.
He'll be under soooo much official surveillance and media scrutiny that he won't be able to so much as litter.
If his mother has even the teensiest, tiniest speck of love or compassion for this kid, she'll pack the whole brood back up and head to somewhere where they'd at the very least not be reviled, forget about being welcome. They'd enjoy a much better overall standard of living in Karachi than Canada. The father cared more for his beliefs than for his offspring, lets hope that somehow the mother is different.