characterization

Oberon's mum


The piece below is part of a novel I'm working on. I'm trying to characterise the protagonist's mother-in-law. Any feedback would be much appreciated.
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Zephaniah
By Lou 2005 (c)

Kirin's mother-in-law drives a minibus. It's not that she's a bus driver, oh no. Her personal vehicle of choice is a second-hand bus she bought for a song five years ago. Having begun volunteering at an orphanage and old folk's home, she wanted the Mercedes bus for ferrying the children and senior citizens on excursions and such. The eighteen-seater works for her – big enough to carry a boisterous party, small enough to manoeuvre around corners and into parking spots. She had the old double seats ripped out and put in firmly cushioned double and single seats. She got it repainted in lime green too. When she's not driving anyone anywhere, she'd put her favourite potted plant of the day in the foot well of the front passenger seat.

Sometimes her muscular short-legged dog of indeterminate breed goes along for a spin – riding shotgun securely strapped into the front seat like a psychotic patient who has just morphed into a wolf.

Zephaniah Rada is the name in the birth certificate of Kirin's mum-in-law. Her ancestry – traceable ones are Irish, Ceylonese and Chinese – is almost as mixed as her dog's. Zeph, as she likes people to call her, named her son Oberon. When Obie was twenty-five years old, he was dating three young women. A year later, he was married to Kirin, the one Zeph had least liked. His mother's complaint was that Kirin was too ordinary – the beautiful young woman, in the eyes of the older one, did not possess quirks, idiosyncrasies or eccentricities.

Right or wrong, Zeph concluded that Oberon, for reasons he didn't disclose and she hadn't asked about, had deliberately not chosen a woman like his mother.