Woodstreet,
It is very difficult to advise ongoing police investigations, but ABH is very serious and is normally when someone causes serious injury to another. All the mitigation (reasons) for the injuries affect the punishment. You state he may have mental health issues, all these factors will be taken into account. Custodial sentences are designed to punish offenders who have been dealt with for serious offences. You don't say if this is his first offence? is thier any history of the problems you state.
It is most important to advise your solicitor of the whole history and any written/ text messages phone calls etc.
However the court will only deal with the charges as detailed.
Hope this helps.
PS The prisons are FULL so the courts will look at other punishments at present.
LMan