Failed   appeal new route to claim ESA

As an appeal was unsuccessful am I correct   in stating that unless decision of FTT is overturned the   only way for a single   man to start to receive ESA again will be   if DWP accept   he   has a new condition?

You client can claim ESA again but it will only be put into payment if DWP accept that an existing condition has significantly worsened, that he has a new condition, or until such time as they carry out a WCA and decide he scores sufficient points (which of course is unlikely in the circumstances you describe).

See this welfare rights bulletin article on the ESA changes ESA and abolition of the ‘six month rule’

There’s also this article which explores some of the ins and outs of “significant worsening” ESA and ‘significant worsening’