1. I neither know nor care.

2. The same standard of evidence we demand for everything else. Plenty of independent corroboration for his apparitions would do for starters. That does not apply to the usual "evidence" for God put before us. Witness, hearsay, ancient tendentious texts selectively presented to us, edicts, ceremony and tradition all fall well short. In sum, we don't know what evidence would be good enough because we haven't had any as yet that is worthy of the necessary scrutiny.