Edema

Edema means his tissues are holding water.
It's a symptom of any number of issues most of which deal with major organs.
Heart
Lungs
Kidneys
Liver
damaged leg veins
problems with the lymphatic system
certain diabetic medications can trigger this, etc
Hopefully the hospital can find the problem and I hope it's easily fixable.

http://www.mayoclinic.com/health/edema/DS01035/DSECTION=c...

edema is not a disease it is a symptom. edema can be related to a number of causes including heart disease. It can also be caused from other reasons such as a skin infection called, cellulitis
Below I have listed a few causes of edema that you can google
Cellulitis
lymphedema
peripheral vascular disease
congested heart failure

There are many things that can cause edema but its a symptom not the desease. Most of the time it is a symptom of a heart problem as the blood is pooling and fluid is leaking out into the tissues. Hopefully the doctors can get the main problem under control and the edema will go away. It's probably been a long term problem if it's infected.

The others are right - edema is a symptom and can be caused by a number of different diseases and conditions. It doesn't sound like you have enough information to give us - we can't really help you. You need to find out what disease he has and what caused the edema. It's possible they don't know yet and are still running tests. Wishing your brother good luck and a full recovery.

I urge you to talk with his doctor. We cannot know what is happening with your brother. You need information that is specific to him. Ask your brother to give the doctor permission to talk with you.

What I do with relatives is be sure to be visiting when the doctor makes rounds. That way I can hear what they say and ask questions because my relative is there to give permission.