I got an ankle brace for when i'm up and walking. when i lay down it's hard to keep ankle still. can i wear brace in bed or is there other devices?

Ankle instability: Try an ace bandage over a cotton sock. do not apply too tight. Your foot should not feel numb or painful when you apply this bandage.

An ace wrap may work: Assuming the instructions you have regarding your brace are that you should remove it at night, it might be more comfortable to use a properly applied ace wrap in bed which could give some support but be less stiff and bulky.

You most likely need: You most likely do not need the brace while sleeping. If you feel you need some compression, you may try an Ace bandage.

Drop foot : If you are wearing a ankle brace to assist your walking, you can ask your Podiatrist to get for you a night splint to wear at night to help stretch out your Achilles' tendon.