Husband woke up with severe cramps in both thighs described as charlie horses. what can /should i do? what symptoms for clots?

Clots unlikely: Cramps in the legs are very common, usually involving the calves but any muscle can be involved. The instant cure is to stretch the affected muscle. You may need some teaching from a physical therapist to learn how to do this. Stretching and exercise, together with healthy eating can also be helpful in preventing cramps. There are also rare reasons for cramps so a visit to your doc is good also.