All 4 of mine get croup to varying degrees - DD1 used to get it particularly bad and even at nearly 8 she had a day off school a few weeks back because she woke up with a croupy cough. However, none of them have asthma at all. DD1 did get Bronchiolitis at 9months old and DD2 had pneumonia when she was 4 but that's it. So there is a chance that he may not, but considering the other issues that are being looked at, it sounds like he will eventually be diagnosed with it.