I was thinking about making a similar comment waffling between being slightly more tactful or much less so WRT said manager. JSON is a standard, there's off the shelf parsers for it that have been extensively tested. If you stick to "just" regexen you're reimplementing a perfectly good wheel for no benefit at the cost of less testing, a custom implementation that may not handle everything valid by the spec, may need tricky extra stuff like embedded code in the regex to get corner cases, . . .

As a learning exercise, sure maybe. Production code? Inane is probably being kind.