I often wake up and don't even feel like eating despite being hungry.
As has been commented, the OP has asked the forum about his dietary issues more than once. I doubt drinking too much coffee is suppressing his appetite (it certainly doesn't affect mine) and drinking lots of water (to keep a "fill" in the stomach) is what is suggested for those who need to eat less. Usually, hunger is the stimulus to eat, and many enjoy eating even when not hungry (which has something to do with the U.S. population becoming heavier). If someone is hungry but doesn't want to eat perhaps there are other issues involved. And, as long as one is not emaciated being skinny can be a blessing rather than a curse.
Some people are just fussy eaters. Having preferences is one thing, turning one's nose up at most common foods is another. I grew up in a farm home where one ate what was put in front of them (usually from the garden, home canned, etc.) and one cleaned their plate before leaving the table if they knew what was good for them. So, I've never understood the "fussy eater" syndrome. Maybe he needs to focus on preparing food he likes, as long as the ingredients are healthy and the meals nutritionally balanced.
There could be underlying medical issues, even if he feels healthy, and a thorough physical with blood work could be helpful. IDK what kind of school he goes to but most colleges have a student clinic that provides basic services at little or no charge. One might also be able to get a basic exam and lab work through the county health department. Providence (one of the large Catholic hospital organizations) has a mobile clinic that visits local food banks and other locations in eastern WA. They do lab work as well as exams, at no cost. There may be something like this where the OP is located.
There are eating disorders, such as anorexia. I'm not suggesting this may be an issue, I'm just being thorough. Many people with eating disorders don't always recognize it in the beginning.
A health physical is probable a good place to start. Constantly searching the interweb or asking forums about "miracle elixirs" and "foo-foo powders" probable not so much.