well mate, i aint very much sure about the procedure but yeah, indeed u can have a residential visa for ur mother (commonly speaking).
it does also depends upon her age as there are a few clauses like if she's exceeding a certain age wich according to me is 60 or 65 then u've to use sm influence or hav really good luck ;)

anyhow, all the best if its for ur mother... hpe u succeed in gettin her wat u desire :)
cheerX