Discussion about land use

My Mum lives in a townhouse complex at Everton Park, approx. 30 years old and with some city views. She told me that last week a developer came around discussing the value of her unit but she hasn't shown me a business card. Her land is 315 m2 in a complex of 30. According to PD Online, it is zoned low density residential which currently does not allow townhouses anyway.

Can the experts let me know what use would the land have these days? I would imagine a nursing home (a growth industry) rather than adding to the gazillions of new townhouses being build all around. It's probably too big for a childcare centre. Low density has me wondering whether the land can be better utilised commercially. The old homes across the road on large blocks are gradually being subdivided and demolished and replaced with 2 story dwellings. The complex backs onto another large older complex in the next street.

I'm after any ideas about its potential use. If zoned LDR, can a developer ask council for a rezoning?