My son and daughter in law adopted a Down Syndrome child. It is working out very well.
A lot of Downs Syndrome folks actually function quite normally as adults especially when they had good early rehab help...many of them are of good average intelligence or can be quite bright. Some, as they grow up to maturity, seem to lose a lot of the identifying physical characteristics and you might not even be able to tell them apart from the normal variant physical characteristics we see amongst human adults. (so we shouldn’t be killing them in the womb!)