Non dependent deductions and temporary absence

This one has me scratching my head, so any pointers gratefully received.

Client is, or was, single parent, youngest son left school in September 2013, started part-time low-paid work as taking gap year before university in September 2014. HB department adjusted payments due to WTC/CTC/CHB stopping, and applied £13.60 p/w non-dep deduction for him.

He wants to go to a Camp America thing in USA for 3 months. Will be paid ~£1,000 for doing so. My primary question is what does this mean iro the non-dep deduction i.e. will it be suspended? It’s a temporary absence but I can’t find anything specifically about the situation - my feeling is that as this remains his “normal home”, that the non-dep deduction might simply continue to be made until he starts uni.

Secondary to that I suppose though is if he was taken to be absent and non-dep deduction ceased, would the bedroom tax than be applied instead as under-occupying (not a problem I think when he actually starts university next year)?

Anyone have any thoughts? Many thanks in anticipation.