Thanks for query,
As as friend you have big responsibility on your head.
to look after his mother it seems you have to play major role.
Come out from stress
and have great will power.
develop self confidence and ready for making his mother fit to fight present situation.
I know you have lost your friend and have greatly distressed.
You take well nourished diet,make your mind strong.
Take B.complex and some appetizer.
ok and take care.