Has there child on treatments for asthma but has not been diagnosed?

My sons acts up only at night not every night but here and there . It’s when he gets sick with the cold or flu it turns into bronchitis or one year it was Pneumonia .And it drives me crazy Bc neither his doctors or the doctors down at my local hospital informs me on what I can do about it . How I can prevent it . It’s just scary feeling when I know my son is getting sick and I know what’s coming after is the worst . Do I give him the treatment right away when he started getting sick to prevent it ?? Orr I just wait ..

I have been told that the meds he inhales also can “reverse it” that’s why he’ll get bronchitis.. so idk .. my mind is going crazy . If any moms has a similar situation or In the same . Any advise can help me .