Rand0m3x: The word ישראל has a KAMATZ under the ר which should be pronounced “RAW”. However, many people pronounce it as if it had CHOLOM which would be “RO”. People usually spell it in English as YISROEL hence the OP’s question.
In EY, Ashkenazi pronunciation of the kamatz is more of an Oh or sound, not oi like a cholom. The patach is what has the Ah sound. It does not matter if it is for the name of a person or the place (EY).
The Sefardim have no significant difference in the pronunciation of the patach and the kamatz, both sound like an Ah.
In America, many people pronounce these vowels like Sefardim.
Kametz, can be an “ah” as in father, an “oh” as in oatmeal, or an “aw” as in “raw” depending on dialect. All are glatt kosher. The “aw” (spoken by western and northeastern European Ashkenazi) is probably closer to the ancient pronounication, but you’ll need a time machine to be certain.
Nechomah: There are those who pronounce it as “cholam” and those who pronounce it as “choilam”. The kamatz is generally sounded as “AW” and the patach as “AH”.