Consider needing to take care of a 40 year-old man with the mental capacity of a child while you're in your 70s. It would literally never end, nowadays they'd outlive you. Sounds absolutely horrific.
Forcing people to carry babies with genetic abnormalities to term, and then to care for them with little assistance for the rest of their lives, will only discourage people from having kids.
This guy made the right choice for his family, and that choice will lead to other kids.