Welcome to the forum though sorry to read the reason that brings you here.  Whilst my  husband was somewhat older when he was diagnosed as terminal (and felt really rough during his palliative chemo treatment) on his good days he enjoyed the company of others provided they did not talk about his illness (his coping mechanism). If he fancied doing something or going somewhere we did our best to arrange it for him.  Perhaps there is something your sister would enjoy such as having a manicure or tea with friends but in my experience keeping such outings short helps with the fatigue that cancer and its treatment can cause.

Hopefully others will be along shortly to offer their own thoughts. Regards Jules54

Thank you for your response. It is very difficult watching my sister so poorly and upset. Cancer is awful!!