A.M.
you have not said one thing to make me think SHE wants things to change. if you feel that you are spending too much time together, politely decline or make other plans. i just don't see one statement you've made that has anything to do with HER wishes.
now if you were to say that she is depressed, seems lonely (not "She is a widow also, no dates right now. So, I know she is lonely" - that does not mean she is lonely, that just means she's not dating), sad, or down a lot, then yes.
i could be reading this all wrong - i have only seen a small fraction of the whole situation. but to me it sounds like you are more interested in her being "social" than she is.
i am not a social person. i have been at different periods of my life, but naturally i tend to be more of a loner. i like being alone. i'm cool with it. she may realize now that there are things more important than being a social butterfly. she might not have the energy to do a lot of things. we don't know what she's thinking. but that is what matters.