Hello
Your son is having temperature (101.4) and after 
paracetamol 7.5 ml + sponging the temp has not reduced even after 2 hours. Then you gave 
Meftal syrup 3 ml.  You like to know which drug is preferred and the time schedule. Last year your son had a febrile 
seizure.
As your son had a febrile seizure, you must take all possible precautions to prevent the temp shooting up. Ordinary tap water Sponging especially in the forehead, 
axilla and groin is important. 
Paracetamol and Meftal have the same 
antipyretic action, whereas Meftal has additional anti inflammatory action taking care of the pain. 
The combination of these two drugs is available.
For your son (13kg) the advised dosage of paracetamol is 7.5 ml (5ml contains 125 mg) 3 or 4 times a day.
And meftal syrup is 5 ml  (each 5 ml contains 100 mg.) 2 or 3 times a day 
When you give in combination the standard dose the Dr prefer is Paracetamol 5ml + meftal 5 ml  3 times a day. I prefer this combination for your son and a consultation with a 
pediatrician as early as possible to determine the cause of 
fever and initiate the treatment. 
Individually for your son paracetamol can be given up to 7.5 ml.
Consult your pediatrician regarding this dosage schedule, and ask him any anti epileptic drugs can be given as prophylactic, whenever your son gets temp more than 100 or regularly for few years.
I hope you understand that
I wish for the speedy recovery of your son
Best wishes to you all