Sounds like your brother is a bit of a romancer/gossiper who possibly gets kicks out of speculation like this.
There was no mention of this on the BBC nor Sky News last night so it must be some conspiracy theorist in Russia on a wind-up.
Spectrum also said that the UK would first of all have to have approval from the USA and wouldn't be able to just push the red button willy-nilly!
Protocols to follow, and all that.