It really depends on the siutation. If the parent is physically
mobile (can walk on his own) and you have someone always around the
house to keep an eye on the old folk, I think it's okay for him to
be in the house.
What if everyone in the family is either working or schooling. If
the parent scully fall down or kenna stroke at home and no one
knows until someone is back...also, getting a maid to take care of
the old folk is also not cheap. Then you have the problem of having
a stranger in the house..you may have heard of all those maid
stories..
My old man is in the old folks home and I am paying about $1.3K a
month to keep him there. He kenna stroke about 3 yrs ago and 1/2
his body knocked out. Cannot walk, eat also have to feed him, can
talk but not clear. Then he has to be turned over in the bed once
every 3 hrs so as to prevent bed sores.. No choice. I'm working, my
kids are schooling...knn...I now damn stretched... 
If I put him at home, scully he fall down again...game over for
him.. 
Recently, while visiting my old man, the staff was walking another
old guy around the ward. The walk was interrupted because he
suddenly pang-sai and a few lumps fell out of his pants...So for
those people who want to keep your old folks at home..can you tahan
picking up the shit and cleaning the old folk up, changing his
diapers etc..everyday..??