Reclaiming ESA after 4 weeks on JSA

A client claiming ESA decided he was well enough to go back to work, he closed his ESA claim and signed on for JSA but it quickly became apparant that he was not well enough to work at all, he has only been on JSA for 4 weeks. 
Can he reclaim ESA under the linking rules even though he was signing on and not working?  or would he be subject to the 6 month rule, whereby he could only get ESA again is he got a new med cert for a different condition or a new medical condition?

To complicate matters he was on ESA assessment rate pending an appeal as he failed the WCA, however a review found in his favour however by this time he had already signed on JSA , does this make any difference to the case?

i think that the review would mean that he retrospectively had ‘full’ entitlement to ESA including a component, up to the point he closed his claim in order to claim JSA.  As he was on JSA for less than 12 weeks, his new ESA claim should be linked to the old and he should get his component back straightaway?