Child missed the first day back at preschool

I feel bad because my son missed his first day back this year. His little brother has the Rona and the adenovirus. This morning my oldest (preschooler/5year old) was sniffling his nose and complained of it burning. I was certain he was coming down with c0v!d too. I messaged his teacher and said he most likely won’t be at school at all this week. I was going to take him to an urgent care that afternoon. As soon as 1pm hits my son is acting fine.

So, do I go ahead and send him to school tomorrow? Or should I go ahead and take him to urgent care and get him tested for it? (Although he is autistic, and I know he isn’t going to let them stick the swab up his nose.)