It's possible, if the attacker controls the device enough. I don't think a big "you're being targeted" warning is something you don't notice, or forget.

In this case he was investigating misuse of Pegasus spyware specifically, and was targeted with it while doing so. That's obstruction of justice, morally speaking, and would feel very scary, in that it would make you feel that this company might be so powerful that investigating it is personally dangerous.

The US does not spy on Five Eyes government leadership or that of Israel. And perhaps more: in the wake of Snowden, which obliterated many diplomatic relationships the U.S. has with other countries, Obama issued a directive that the U.S. would not monitor heads of state and government of close friends and allies (even outside Five Eyes) unless there was a compelling national security reason. As far as we know that directive has remained in force with each successive administration as well.

They spy on most others though. Germany’s Merkel, successive French presidents etc all had their phones hacked by US there is widely reported news of.