Analyzing Sharon's birth chart and transits starting  March 2005 it seems that this stroke and coma were undoubtedly written there. 

At the beginning of March 2005 a disaster constellation  of Chiron, Pluto, and Uranus have reached and were sitting  on very sensitive places in his birth chart, making disharmonic aspects towards his natal Sun, Chiron, Pluto, and Moon.

The stroke: Chiron conjuncted his natal Mars, and later also made a square to his natal Chiron. It started on 3/2005 for 2 months and stopped due to Chiron retrograde, but it started again on 11/12/2005 which indicated on things that are about to  dramatically  changing.

Transiting Uranus conjuncted his natal Sun at beginning of March 2005, retrograded and stand again on the same point, conjuncting natal Sun on 18/12/2005, the exact day that Sharon emergency moved to Hospital

But above all transiting Pluto made constantly, since March 2005 (alternately until this October 2007)  of two aspects:

1.        Pluto inconjuncted his natal Moon, symbolizing again a far-reaching changes and crisis

2.        Pluto made quintile with his natal Sun. Although quintile in a birth chart may indicates a special talent, in transits, especially of Pluto and Sun it may symbolize matters of death and re-birth . transits to sun affect one self-expression, creative potential and a sense of well-being, which can radically alter, also physical vitality is also affected . This significant life changes are almost certain to result and they may come slowly and painfully.

 

These aspects between  Pluto and Sharon's  both Sun and Moon happend  on and off, depending on Pluto's  retrograde. They've started on  March 2005 (his first stroke; 18/12/2005 was his second stroke followed with coma) until 2007. As we can see this aspects are stopping during midst October 2007 something that might indicates that this situation of Sharon's coma might change.