Ken! Welcome Big Guy! Glad you found OCF, Sorry you had to brotha!
I'm going to use my favorite quote here, "He who has a "why" to live can bare with almost any "how"." -Neitzche
As a family man myself brotha, my wife and two young boys were my why, and because I have them I'll walk through hell to stay with them, and I know you "get" that.
Getting through this experience and then learning to live with the aftermath requires help...remember that you are not alone and that no matter how macho we try to be as men, everyone needs help, especially in this situation. It does my heart good to see you on these forums my friend and plugging in, that's the hardest step for a lot of men to take.
The only thing we can control, after we've chosen our medical team, is our nutrition and attitude, and both are of the utmost importance making it through this ordeal. Nutrition is important in everyday life but even more so when your body is being severely broken down, which is why I view treatment like high intensity PT and recommend eating like you are a high level athlete, training to be a champion. You are what you eat.
Proper nutrition when it comes to cancer patients isn't very well understood really as our Dr's are poorly trained on nutrition and our nutritionists really don't understand what the body goes through when battling cancer, there's a disconnect there sadly. The system of a cancer patient goes into a hyper-metabolic state due to hormones produced by the immune response to the disease. The hormones reduce the amount of nutrition absorbed through digestion, while the body directs the lions share of amino acids to the immune response. This causes your body to start breaking down it's own lean muscle mass for fuel causing a significant weight loss. It's a wasting condition called Cachexia, or cancer related weight loss.
This is important to understand so you can battle the condition, also patients with higher percentages of lean muscle mass have higher survival rates and generally withstand treatment better. Muscle is a fast burning fuel for the body and it will catabolize that tissue first before our fat reserves which is why proper protein intake is critical. Protein provides the body with the building blocks (amino acids) it needs to repair itself, that being said, not all protein is created, nor absorbed equally.
The benchmark or "gold standard" for protein is the egg. For myself, I lived in the gym and competed at the collegiate level in athletics so nutrition, and the benefit of eggs and whey protein were drilled into me. The egg has a biological value (BV) of 93, is packed with vitamins and minerals, good fat, and it's protein is efficiently absorbed in the body. The downfall to eggs is to get the amount of protein you need it takes a "lot" of eggs and eating is a challenge in our circumstance, so protein powders makes sense.
Now the three common types of protein powders are Whey, Soy and then the Vegan/Vegetarian powders that use mixed plant based proteins to get a "complete" (all essential amino acids) powder. The difference between these proteins are uptake or absorption rate and the obvious dietary restriction based on personal beliefs/preferences.
Whey has the fastest uptake/absorption rate of all the proteins, it's BV is over 100 (higher than an egg) and is the choice for most serious athletes and bodybuilders. In everyday life if you are not training heavily or constantly breaking down your body to rebuild it, Whey doesn't make sense due to it's fast uptake as the body will only absorb what it needs at that time and then pass the rest. This is also why protein intake needs to be divided up through several small meals throughout the day with no more than around 30g taken in at one time, 20g's is what's recommended for regular activity levels, 30g's for those with higher.
Soy and plant based protein powders are around the same BV as the egg, soy having the same uptake value and the plant based being a little slower. These proteins are usually recommended for everyday activity levels as a slower uptake generally leads to better absorption as your body isn't in a hyper-metabolic state and sucking up nutrients as fast.
It comes down to a game really, using nutrition to manipulate hormone responses in the body and promote recovery. Athletes and top level trainers use a specific ratio as a guide for macro nutrient (protein, fats, carbs) intake to ensure performance, which is 40-50% of the calories through carbs, 20-30% protein, 20-30% fat, which is coined as "The Golden Ratio". To understand where your levels are at you have to count calories and macro nutrient intake, which is made easy by today's smart phones with apps like Calorie Counter by Fatsecret(which is what I use). To get the % just know that proteins and carbs hold 4 calories per gram, and fats hold 9. Multiply the number of grams in the respected macro-nutrient by how many calories it holds, then divide that number by the number of calories taken in during the day. Example on a 2500 calorie per day diet, 55g-83g of fat, 125g-185g of protein, and 250g-312g of carbs (complex like multigrains etc). 2500 x percentage desired (.2, .3, .4, .5 etc..) then divided by 4 for proteins/carbs or divided by 9 for fats.
Why is this important? Your body needs the proper fuel and building blocks to fight, rebuild itself, energy and hormone production. Testosterone, arguably the most important hormone in the male system (key in muscle development, mood stabilization, outlook, sex drive etc...) can be largely promoted by nutrition. The more good fats (mono unsaturated and poly unsaturated, MUFA's and PUFA's) in a man's diet the higher the testosterone production. Too much protein can lower testosterone production (as well as pain medications, antidepressants, stress, anxiety...) so it's important to keep balance there. Testosterone is key in building and maintaining muscle mass as is protein.
Personally I use Whey due to my lifestyle (lifting and heavy exercise) as my main source of protein, I also juice fresh fruits and vegetables, blend oatmeal and other foods to sustain my weight (I'm on an all liquid diet) and religiously keep to my nutrition plan, tracking it all by Calorie Counter by Fatsecret on my android phone (iPhone app too).
As far as keeping your spirits up and a great attitude, keep plugging into these forums for advice, support and friendship, it's what we do. I read uplifting, inspiring books, music and movies to keep me in the right mindset throughout the day as well.
Good luck my friend, I apologize for the book..nutrition is a passion of mine