paragraph 2:

intravenous --> intravenous infusion or intravenous drip(s)

begin with two days of intravenous --> two days of intravenous infusion to begin with

the side-effects of the prescribed intravenous-->
any adverse reaction to the drugs (or the prescribed intravenous)

paragraph 3:

Then my child said that she had a painful leg, so my wife, my mother and my child’s aunt brought her to the same hospital again. -->
Then my daughter said that she had a painful leg, so my wife, my mother and my daughter’s aunt took her to the same hospital (or health center) again.