To do this, You would need to Find code for Checking the Healthbar of a pet (Pixel Scanning through EUO), and then after that its pretty straight forward 
set %Pet XXXXX ; Id for pet 
While Penguins <> Leprachauns
{
Gosub Get_Health ; <- The code to actually check health you would have to get from someone else. 
if %Pet_Hits < 80 
{
Finditem (Heal Potion Type) C_ , #Backpackid
if #findcnt = 0 
Halt
set #lobjectid #Findid 
event macro 17 0 
Target 30 
set #ltargetid %Pet 
set #ltargetkind 1 
Event macro 22 0 
wait 20 
}
}