UC reassessment severe, lifelong disability

My stepson has been blind from birth. He went onto UC two years ago from ESA after moving to a full UC area. He is in the LCWRA group (achieved with help from this site). Our understanding was that as he has a "severe lifelong disbility" he will not be subject to reassessment. However, he received a call today telling him that he has to be reassessed and forms are on their way.
Are we right in thinking he should not be reassessed and if so, how does he go about challenging the reassessment?

Hi Gordon, my understanding is that as of September 2017 people who meet the criteria with a severe lifelong condition in the support group or LCWRA will not have to be reassessed for ESA or UC disbility elements
www.disabilityrightsuk.org/news/2017/sep...eassessment-criteria
However, it seems that the decision will be made once you have had an assessment after that date. In our case, the last assessment was in 2016 so he will have to have it.
www.disabilityrightsuk.org/sites/default...nditionsguidance.pdf

Thanks, we're now aware of the criteria to be met so we'll try to give ourselves the best shot when facing the WCA. Do you know if it's now on the application per se, or if there's a way of flagging it up as a consideration? The inability to appeal is concerning, even if the guidance is not adhered to

My understanding is There are a few health conditions associated with exceptions to reassessment, but are mainly life threatening conditions, as Gordon said cancer etc. I would think the view of DWP don't find your sons condition life threatening, although as you say is a lifelong disability is not a threat to his life? You don't receive severe disability premium whilst claiming universal credit.