Weakened villagers are not sick, so they can not be healed. Mostly they just need some rest or (a lot of) food or water.
When nursing mothers die, their children die with them.
Villagers do not breed if they are hungry or sick and sometimes it just takes a lot of times breeding to get a child.
The wishywashy sounds? May be they are drinking from the well, maybe it is the waterfall.

How is your food supply?
What level are you with farming?
Which puzzles have you solved?