Yeah. Martial arts are hard. Get over it.
Or, alternately, martial arts are no harder than getting (and keeping) a job, handling your teenager's issues, talking to your neighbor who plays loud music at 2 am, or dealing with the death of a loved one.
I understand that for many practitioners, martial arts practice is the catalyst that causes them to start to notice and experience all kinds of new things and develop new abilities. This is where the "aikido is my life" thing comes from, IMO, and where you get people claiming that they "used aikido" to deal with a difficult situation at work. It's sort of true for them, but only in the sense that if the only tool you have experienced is a hammer, then "hammer" is the extent of your vocabulary to talk about tools. The reality is that our lives are full of the challenges and epiphanies that many martial arts enthusiasts believe are exclusive to, or inherently tied to, martial arts training. And it's quite likely that the individual in this case has already lived quite a bit of life, and has faced worse rejections and more devastating reassessments of himself and his abilities in other contexts. It's possible he faces more daunting challenges every day. Just because we're inclined here to invest our progress in aikido with so much significance, don't forget that it's just one part of a much bigger series of challenges. The next rank is a huuuuuge deal to a 9-year-old yellow belt in a suburban taekwondo school; it's not likely to be such an enormous thing to an adult.