What Causes Skin Weeping From The Arms, Body?

My mother in law, 88 is in hospital now with pneumonia. She has many health and respiratory issues for which she is being treated, including irregular heartbeat, high BP, etc. She had a stroke 1 year ago. The last couple weeks, her arms are extremely swollen and her feet - not her legs.The nurses said today that her skin is weeping fluid and they need to change her gown every 2 hours. What is causing the skin weeping from her arms, body? Thank you.