I mean I wouldn't want her to keep them. Taking on four kittens when you already have a bonded pair of young cats is irresponsible. Although it breaks my heart they've been outside for that long.
Obviously I don't know what the rescue situation is wherever she is, I just find it surprising. The rescue charity we recently homed our small furry compadre from are packed to the gills but are regularly posting about how they're all systems go as soon as a brood of unneutered kitten strays are found, collaborating with other rescues as necessary to get them to where they need to be. And they're a tiny operation mostly staffed by volunteers.
WFK.