Sorry, Emergency accommodation is only temporary and not a permanent checkable address, if he was living in emergency accommodation before he went to prison that is going to be a problem for release on 'tag'.
As soon as he went into remand his emergency accommodation would no longer be available to him so officially he is regarded as 'homeless'.
As I said they can only 'tag' you for release to an address that is your genuine residential home address, and he does not have such an address.
So I am sorry, but I do not think he can qualify for 'Home Detention Curfew' or 'Tag'. He will have to wait until June and serve his entire sentence in jail.
I know it's too late now but if he had accepted his barrister's advice to plead guilty to S20 he would have been released straight after the sentencing hearing. Remember this as a lesson if anything happens in the future!