I had played fortnite battle royale with my wife. She was on pc and I was on ps4. People doubted me that you could do this. I even emailed epic and they said it was not possible but it actually is. You have to follow some specific steps.
- link your epic games account to your PS4 psn account
- have your friend on pc send you a friend request
- load up the epic games launcher on pc/mac to accept that friend request (you won't see it on the ps4, has to be done on the epic games launcher)
- now that you are both friends . both PC and PS4 players need to load the game up
- the PC player should be able to now see the PS4 player in their friends list
- the PC player should be able to join the PS4 players party and play together.
I have made a video demonstrating this is possible.
