My mother-in-law is in an assisted living facility, which she refers to as a prison. She actually chose this facility as her future home prior to suffering a stroke but is now unhappy. She is the only person that does not think she is receiving the care she needs. Aside from encouraging her to participate in facility activities and encouraging visitors what are some others things we can do (decor in her room, etc) to make her feel more at peace with her new home and perhaps distract her from feeling as if she no longer matters to anyone?
We did personalize the room. Familiar bedspread. Chair. Lamp. Can you skype with family members that aren't local? That would be an activity for both of you. Good luck and let us know how it works out.
But she's had a stroke. How long ago? The reason I ask is that both depression and extreme fatigue are very common after-effects, so that I suspect that her unhappiness stems more from how ill and tired she feels than from any shortcoming on the facility's part or yours. You say - this is very sad to think of - that she feels she no longer matters to anyone. Unfortunately that belief comes from within her (or more accurately from her poor, injured brain), not from external reality, and so there is very little you can do to convince her otherwise.
Her mood may lighten in time; and it is worth checking that her PCP has addressed it, too, because there may be help available for it. But other than that, sadly, the only really effective answer is to adjust your expectations of what you can reasonably expect of her.
One family I know turned their mother's bulletin board into a family tree with labled photos that branched out from mom's wedding photo. It was a great conversation starter!