I agree with your husband that giving money to charity is a good thing . If always tried to give away a reasonable proportion of my disposable income .
BUT I would only do that after taking care of my financial responsibilities to my children . So in your case I would first pay off the mortage, ensure the house is in good repair and invest money for the children's education.
Of course they shoudl make their own way in the world,, but unless you have a family business for them to walk straight into, they need a good university education. And that's very expensive, especially if you live in England .
His kids won't be very impressed if he gives it all away and then they can't go to university etc because they can't afford it / he drops dead / runs off with his secretary
I agree with everyone who says get him to put it away for a year until he can get Financial advice. Then you can look together at the options .
He needs to do some serious research on any chartity he wants to give it to. As others have said, it could end up being wasted on a years salary for some celebrity " chairperson " or private school fees for staff kids.
Someone I know who has some family money ( and no kids to leave it to ) has invested it and each year, uses the income to sponsor some post graduate students ina a university department. It's in a fairly niche subject where this couple have a particular interest and students come from all over the world .
I think they sponsor about 3-4 students a year at about £10k each . They also gift lump sums for capital projects for equipment , but they get far more pleasure from meeting the students and hearing about their research and the impact they are making.
So it's quite possible to invest money wisely in a charity but it takes TIME and EFFORT and THOUGHT. Which your husband doesn't seem to have much of at present .