The claimant's HB may stop even though, looking at the temporary absence rules, they should be entitled to HB. This is probably because the HB Office are not aware of the claimant's current circumstances and have just been notified by the DWP or Job Centre that the claimant's IS, ESA or JSA (or UC for those living in specified accommodation) has stopped.
The HB Office will then have suspended HB and written to the claimant for information on their current circumstances. If the claimant fails to reply to this, their HB claim will be terminated.
You can inform the HB Office what you know about the claimant's circumstances - better still is for the claimant to contact the HB Office.
Someone else left in the property?
If the claimant is unable to claim HB (for example they may not intend to return, or may exceed the 4/13/52 week time limit for being away temporarily) then there may be someone left in the property who could claim instead such as a partner - click here.
Other people left in the property may in certain circumstances be treated as liable for the rent even if they are not the tenant or tenant's partner. They can then claim HB themselves.