He has a video! https://www.youtube.com/watch?v=BD3my03ioioI would like to see Legal Eagle's view on this he's usually very good at explaining if he does indeed have the right in this case. He's also very anti trump refusing to call him President Trump and calls him Mr Trump.
I'm no lawyer but I don't think this impeachment enquiry legally falls under the kind of jurisdiction where you have that right until it's during a criminal trial in court, and not during an inquiry.
Even if it did it doesn't stop the evidence speaking for itself and any successor to Trump potentially pardoning such a whistleblower. Or a whistleblower fleeing the country such as with Edward Snowdon {shrugs}
I'm glad it's getting Trump scared.