I am a 24 year old male with similar pains as your cousin. It started being a noticeable problem when I was 20 or 21, and while it has come and gone to some degree, anytime I wake up early (usually before 7am) I have pretty intense lower abdominal pain. It feels similar to a bad stomach cramp. I have had varying levels of exercise and eating habits with no real change to the pain.
I saw a doctor and they recommended strong antacids, which did no good. Luckily the past two years I have been a grad student which doesn't always necessitate waking up early, but I have been getting up earlier lately and start work soon so I am a little worried that I will be in pain every morning pretty soon.
Also, I am usually groggy in the morning as well no matter what. It usually helps to drink water before I head to bed, and oddly it also helps me to have a small amount of caffeine moments before I go to sleep. I am not really sure how healthy that latter alternative is though.
Any ideas out there for us?