My ds hated water also when he was a baby!! Now he loves the stuff!!!
We just kept trying him with it between the feeds and he eventually started drinking it, maybe only an ounce at a time but it was better than nothing.
I asked my doctor about it and she said to make a weak formula using only half the amount of scoops to the water but i don't know if this is totally safe, so we didn't do that.
As for the prunes i would guess you just boil some and then sieve it just incase any bits are in there, wait to cool and then offer to baby.
If you are worried i would see your doc or health professional for advice.
HTH