I'm really not trying to be cute, but how about sad? If that doesn't quite do it for you, look up sad in a thesaurus and go wild."An old mother has long been taken care by her 6th daughter's family where they build up very good relationship. Now, that family will move out shortly and the old mother will be living with her 3rd daughter's family. (both daughers' families love the old mother very very much)"
1) The old mother is feeling sad for the leaving of her 6th daughter's family. What should I describe the feeling of the old mother?
Again, not trying to be cute, but what's wrong with adjustment period? No? OK, how about period of adjustment? You can change this to a variety of things, but you can't improve on it all that much.2) the 6th and 3rd daughter's family will live together with the old mother at the beginning, then the 6th daughter's family will move out until the old mother has picked up the change. What should I name this adjustment period?
She keeps her feelings bottled up inside; she tends to internalize things; she might feel cut off from others; she sounds fiercely independent; she doesn't want to burden others with her problems.3) The old mother does not like to ask for help and always keeps her problems and feelings to herself which caused her depression. What should I best describe this kind of charactor?
This one could be a bit clearer.4) What should I describe one who always think of the extremes of a single case where eventually seems no way out for a solution?
Sorry I couldn't be more help. Maybe others can offer something more inspired.