Why do villagers get weakened? And how do I get them healthy again?

They are weakened by starvation, disease, on-the-job injuries, old age, and Island Events, to name a few. The only way to get them healthy again is to eliminate the cause of their deterioration (get more food, heal them, etc.) and allow them to rest and eat. Taking them to the food supply and repeatedly making them eat will improve their health.

Okay, thanks!

In the game I am running now, I had a series of events that nearly destryed my tribe. The village reached 23 when suddenly they were hit with chickne pox, a flock of parrots, a swarm of locuts and a balmy summer that molded food. Another bout of chicken poxes came right after. After working like a madwoman to keep them barly alive, the next morning I awoke to find only Spice 47 and her half brother Mazi 32 alive and burying their family. Both very weak. The story of the Hard Tribe inspired me. So with enough tech points and Spice a Master Farmer, I let the game run. I believe the extra tech points to reach 3 in farming saved their lives. Spice found the majic fish while Mazi buried the dead. When I got 1000 in the food bin, I allowed them to mate. They had two boys, two girls, a set of twins, girls and fouund a cart of twin boys. Spice sadly died a nursing mommy. The children were coupled; the eldest boy to the eldest girl, the twin girls to the twin boys. Now a tribe of ninty with the Golden child. Never give up on your weak; they can overcome.

Does the baby also die if the mother dies during nursing?