The most important thing I urge you to do is seek God's wisdom as you consider this matter. I've seen families literally torn apart through an unwise use of money - and I've seen families brought together when money was used wisely and selflessly.
Let me suggest you and your husband begin by finding out as much as you can about your daughter's actual situation. For example, is her husband receiving unemployment benefits, and if so, when will they end? Does their state offer some kind of retraining program for unemployed persons, and if so, is he willing to consider it? What major bills do they owe (such as a monthly mortgage payment), and are they in danger of getting behind with any of them? In other words, don't jump to the conclusion that your daughter needs your help unless you know she does.
At the same time, try to put yourself in your daughter's shoes (as best as you can), and imagine the stress she and her husband are facing. We can't always solve our children's problems, nor should we always try - but our love and concern for them should never end. The Bible says that family members should "put their religion into practice by caring for their own family" (1 Timothy 5:4).