Can I only get Cobra coverage for my husband if I was the group health plan participant and he a beneficiary?

In other words, I was the primary insured on the plan. Now since he had a very minor back surgery, they said it is a ';preexisting'; condition when I applied for insurance coverage and would only offer him a short term policy. Can I get the Cobra just for him or do I have to get it too since I was the primary insured on the plan?I am healthy so getting a non cobra plan is not an issue for me and cheaper.