Let's start with her phone being "hacked."
Not likely. Any/all of the following would have to be true for there to be any possibility that it was "hacked:"
- The phone was jailbroken.
- The phone would have had to have been in the physical possession of someone else.
- The phone would not be associated to her Apple ID and was not in her Apple ID device list. This would have disabled Activation Lock.
- That "someone" would have to know her phone's passcode.
- That "someone" would have to know her Apple ID credentials (username & password).
- That "someone" would either have her exact fingerprints (for Touch ID), or look exactly like her (for Face ID.)
- Just connecting to an unsecured Wi-Fi network does not "hack" the phone. However, it is important to note that iMessages are sent encrypted; whereas, SMS text messages are not.
Are these text messages, SMS text (green) or iMessages (blue)? Is she claiming that she is NOT sending them to you ... and they are just randomly being sent from her phone?
Would they affect your iPhone SE? Most likely, not. However, if they include links, do not select them. Just select the message, and then, submit them as "junk."