User blog comment:Morganacharmedfan/questions/@comment-5105486-20121102092308

1. Well I think that she thought that only Emrys could be powerful enough to control a dragon (and she had been obsessed with Emry the whole series so it doesn't surprise me that thought of him immediately)

2. I'm honestly not sure if he's still using it but I wondered that as well

3. Probably because in her opinion a dragon who's loyal to Emrys would never save her life (remember: Emrys is her doom)

4. I think after Isolde died he left Camelot (mayby her death was too painful for him)