Dealing with a pathological liar

Me ex is a a pathological liar - I cottoned on just over a year ago when he started telling some pretty far fetched and unbelievable stories when challenged on certain things. I've caught him out with hard, fast proof yet he still looked me in the eye and denied. He's really ramped up since perhaps September last year. The things he has lied about since they, you wouldn't believe! Now we are no longer together I only have contact with him regarding the rental we lived in together when I left him. This weekend takes the cake, though. Supposedly taken to hospital by ambulance as he injured himself. I wake up to a message through his WhatsApp from a so called nurse saying he had surgery and there were complications and is in high dependency etc. Didn't say which hospital or anything. I am still his next of kin as he hasn't changed it - I would have thought they'd ring as he wouldn't have his phone if the story is correct. Upon calling all the major hospitals around, there is no trace of him and it's been confirmed there was no ambulance pick up yesterday evening. How do you stop stuff like this doing your head in? Love to hear from anyone who's in a similar boat please!