Hi Bubbles, welcome to TP
As Pete has said you really need to get some professional advise and as Rosetta says there may be tax implications if you take out money as a lump sum and a lot depends on the type of pension he has.
It could be it's his pension alone or it could be if he predeceases you then you still get some or all of the pension, in which case taking money out now might cost you in the long term because if he predeceases you and the pension stops you may be worse off and if he ever needed to go into care you would get half his private pension for yourself whilst he was in care, cashed in in his name and it could all go in care costs.
It's an absolute minefield sat on top of quicksand, a "good" decision made now might turn out in the future to be the absolute worst decision you could make, only time will tell.
My wife was diagnosed mid 50's and nearly 10 years later I can't see any reason why she might not outlive me and I'm only 63 last month, I never saw her diagnosis as an end of everything, we just carried on as normal for years before things changed.
There's a whole load of in depth questions about your personal circumstances, debts, income, financial commitments and all the rest which obviously we can't go into on here but only someone who can do a full assessment of your overall situation can make an informed decision and even then it's still a gamble.
You could start by asking your local Citizens Advise Bureau (CAB) or AZ Society as even if they can't help you they may well be able to point you in the direction of local financial advisors who are known to them and are specialists in this area of finance.
As I say it's a minefield, get it wrong and long term it could cost you a lot more than you might think.
K