I have to ask , 1 year for driving while disqualified ? The no insurance is not relevant as by definition you can not be insured if you are disqualified from driving, so you CAN NOT be charged with both !
The maximum sentence for driving while disqualified is 6 months which is automatically reduced to 3 months, normally served in an open prison as a Cat D inmate with release on tag' for the last month.
Has your husband been sentenced for more than you have told us?
Did he reveal his sight problems to the DVLA ? they are relevant and may well have been grounds for canceling his licence, may this be why he was disqualified ? That could explain why he got a year. Sorry I do not mean to be rude but something does not add up here. Under normal circumstances I would not expect a simple driving conviction to end up in Wandsworth even for assessment.
By the way while you are on to the prison lawyer about the medical issues you can put in the claim for compensaton for the damage to his sight, the same law firm will handle both for free . Should easily be worth £20,000 >£30,000 ! I mean it , you have a cast Iron case ! Sue them ! you can not lose !