Is it possible for someone deemed mentally incompetent by the court to regain some rights after further evaluations?

My sister-in-law suffered a stroke early in 2017....she was deemed mentally incompetent and a court-appointed guardian became the guardian of her health.....since then he has become the guardian of her property as well.....my sister-in-law has made significant progress over the last year and a half....despite that fact the guardian is unwilling to share any of her financial information, and will not make any bank statements available to her...….she has no other family members looking out for her other than myself...….I don't think she wants to reassert any control of her finances, she just wants to know how much she has (her husband, my brother, died in 2016)……..just wondered if there were any options for her......it's too bad because she really has made a lot of progress over the last year....thanks for your time....