Guidelines here on GBH
http://www.cps.gov.uk...ily_harm_with_intent/
Cases with 17 year olds quoted involved stabbings and were generally of the 2-3 years basis - but one initially non-custodial but was overturned as unduely leniant on appeal by the CPS.
Difficult to say without further details but I think even if he got a non custodial sentence it would almost certainly be overturned on appeal.
Did he kick your husband in the head? that would be seen an an aggravating factor