Sorry I can’t provide good news; the Move to iPhone app only works on a working Android. However, email accounts, which also include Contacts, Notes, Calendar events and Reminders can be added to the iPhone and this content will be available when you log in to the email accounts. If his Android used gmail as its primary email account then just adding the gmail account to the iPhone will take that data along with it.
For photos, if he used Google Photos, he can add the Google Photos app to the iPhone and access photo and video content. If they are backed up on a computer they can be imported into Apple Photos.
WhatsApp is trickier; the best place to check that out is https://faq.whatsapp.com