Children falling Ill frequently. 20kgs.

I have two kids aged 6y and 14m. Since July this year both of them are falling sick with fever cough and cold very frequently (twice every month on an average). Started with the elder one being diagnosed with ASOM after an episode of cough n cold with fever. Then younger one had the same episodes without the ear getting infected.. Then the older one had another ear infection which was not as severe as the first one - got treated, again the younger baby caught the infection. Now in Sept-oct also the same thing.. Boy had high fever and baby girl had loud cough with mucous at around the same time. After boy's fever he has rashes all over. But baby is still coughing occasionally, has blistery painful eruptions on knees and small rashes all over the body. Local pediatrician gave Relent+ 2.5ml, Omnacortil forte snd Levolin inhaler. She doesn't have fever but occasional coughing. Kindly suggest how to handle this. Attaching pictures. Baby weight 8kgs. Child weight 20kgs.