Barry Allen's death in the comics is a complex situation. Sometimes he does die, but often there are plot twists and resurrections as part of the ongoing comic narrative. It all depends on the creative direction of the writers and the demands of the story at that time.
In certain comic versions, Barry Allen is indeed identified as Jewish. This aspect is sometimes incorporated into his character background and story arcs.
One of the best Barry Allen stories is 'Flashpoint'. In this story, Barry goes back in time to save his mother, which has a huge impact on the entire DC universe, changing the relationships and nature of many characters.
The age of Barry Allen in comics isn't fixed. It changes based on the plot and the creative decisions of the writers. Sometimes he might be shown as younger, and in other arcs, he could be a bit older. Generally, though, he's around the 30-year-old mark.