Welcome to OCF! We're here to help both you and your brother with info and support.
Im sorry to bombard you with questions but this helps to better understand the situation your brother is in. Are you staying with your brother? If not, is he by himself? Does he drive himself to treatments? How do you know he is really drinking 100 oz a day of water? Thats ALOT!!!
My biggest concern with everything you wrote is his dark urine and not going to the bathroom often. Running a fever is also a sign of an infection. If he truly is drinking 100 oz a day of water then his urine would not be dark or lesser quantity. He also would not need the extra hydration. Chemo can affect the kidneys. When patients are in the end stages of rads, it becomes very difficult for them to keep up with their intake. Their ability to swallow, sense of taste, pain, nausea, mouth sores and general overwhelming fatigue all seem to come together to make the patient one miserable person who feels horrible. This plays a huge role in their daily intake decreasing which in turn starts a vicious cycle of not feeling well enough to eat and drink then by not keeping up with their intake other complications like dehydration and malnutrition start making the patient feel even worse. I suspect your brother is starting to have all the nasty side effects I mentioned which in turn makes him avoid eating and drinking. Its so difficult eating when everything tastes like cardboard, is difficult to swallow, hurts the painful mouth sores and takes so much effort it wears the patient out just by chewing. If he doesnt already have a feeding tube, now is the time many patients start going downhill and end up getting a temporary nasal feeding tube. This is something to discuss with his treatment team, ASAP. Every single thing you mentioned needs to be relayed to his medical team. If his urine is dark, less output and he's running a fever he may need hospitalization to pull him out of this downward spiral. Sounds to me like he has a UTI (direct result of not taking in enough fluids) with dehydration and possible malnutrition. One positive thing is he has not lost any weight. Once the weight loss starts it quickly becomes a big problem as patients also are losing muscle tone too.
I ended up hospitalized several times for dehydration and malnutrition. Those 2 things together will make a patient feel absolutely horrible! I was so sick towards the end of my rad treatments from dehydration and malnutrition I couldnt even walk into the hospital, my 17 year old son practically carried me to the car and put me in a wheelchair to get me into the doctors office. The receptionist took one look at me and sent me right to the back to avoid scaring other patients in the waiting room. My doc walked into the room and saw the state I was in and admitted me before she even talked to me or even checked my vitals. A UTI can very quickly become a serious issue when its paired up with dehydration and malnutrition. I do not want to cause you any worries, Im just telling you what happened to me as a result of being too worn out to set up my feedings and sleeping all day. I did not have a caregiver, my teenage children had no idea what to do when I started going downhill. If my son hadnt got me to the hospital (45 minutes away) I probably wouldnt be here.
Drug stores carry UTI test strips so patients can test their urine themselves and know instantly if they are having a problem with not getting enough water. They usually arent right on the shelf and you will need to ask the pharmacist. Usually patients who are at #26 of their rads are having problems swallowing and with painful mouth sores. If your brother has trouble drinking water due to it being so thin, he can pick up some Thick It at any drug store, maybe even at some grocery stores. This will make liquids slightly thicker so its easier to swallow. Talk with his doc about this. He may need a barium swallow test to ensure what he swallows is not going into his lungs. As mentioned earlier, your brother may need a temporary nasal feeding tube if he isnt able to eat and drink enough on a daily basis. Insurance will cover prescription feeding formulas only when the patient has a feeding tube, over the counter nutritional drinks normally arent covered.
Rads is cumulative and continues working even after rads ends. It gets progressively more difficult as time goes on. Your brother is almost at the worst part of it where most patients are beginning to realize just how bad treatments are and they start to really struggle. The worse they feel, the less they take in and the less they take in means the worse they will feel. To get as far as your brother got without losing any weight is excellent!!! Most patients dont do as well, losing significant amounts of weight. Losing weight rapidly is a sure sign the patient is having a rough time. I cant stress enough how important it is to focus on what is within your brothers control... his intake. Dont be surprised if your brother is not being completely honest about his intake. Im normally a very honest person but when I was at some of the lowest points, I would fib about my intake so nobody bugged me about it. I wasnt up to having big in depth conversations when feeling so bad. Every single day during rads and until he hits the first year post rads mark, your brother needs to take in at the very least 2500 calories and 48-64 oz of water. The better patients do with their intake, the easier it will be. If he can push himself to do more and get 3000 or 3500 calories daily that is even better. This is something I always nag about. I hate seeing anyone going down the wrong path and having a hard time when they can turn things around just by taking a few extra bites or sips. I completely understand just how difficult rads is on most patients.
I hope your brothers medical team are able to help him out from this downward cycle. Keep us posted. When one struggles we all struggle. Best wishes with everything!!!
PS...Heres something that may help, our list of easy to eat foods. These have a smoother texture and are mild without alot of spices that can burn a patients sensitive mouth.
List of Easy to Eat Foods