Find small ways to recharge. Ask a local clergyman to come pray with you. Go for short walks. Take small, boquets of flowers to others in the hopsital who may not have any visitors.
Eat good food for your health. Eat comfort food for comfort. Play card games, tell jokes, share memories. Make videos to show your brother that he IS improving. Your brother knows you are there. Do things that will help him and you.
Higs, sweetie. You and your brother are still in my thoughts and prayers.