Hi,As you are saying your child has cough, cold and sneezing ,most common cause is common cold
,I do not recommend you to give omnacortil
which is steroid for this.
Try the following advise
1Give him plenty of fluids.
2.Steam inhalation (very carefully).
3.Antiallergic and decongestants drops can be given for cold and cough.
ca be given for fever.
Consult with good pediatrican in you area if child will have any of these danger signs
1.Breathlessnes: increase respiration,difficulty in breathing
2.High grade fever
3.Decrease oral intake
Omnacortil usually causes vomiting if given empty stomach, it also causes gastritis
Child still not started to sit on his own,needs complete milestone evaluation by pediatrician
.Child usually starts to sit between 6-8 months of age.
Wishing good health for your baby.