Most whiners enjoy whining only when they have an audience. Has this guy always been whiney around you, or has it increased as of late? If it has increased, perhaps he is feeling that you are a "safe" person on which to unload all of his grief. Beware, though: this is not usually true "grief" –Â*people like that really do derive some pleasure from putting on a whiney show.
There are a few tactics that work: 1) try to change the subject, or turn the object of his whininess into something light and humorous. Often being able to find humor in vexing situations can diffuse the urge to whine. 2) See if he really is trying to reach out for help. If you feel that under the veil of whininess is a deep problem, see if you can make parents, coworkers, or mutual friends aware – whatever the case may be –Â*so as to help intervene. 3) You might need space. When he lashes out at other things, he might not be satisfied with your friendship, but may not wish to tell you. If your relationship is strained, sometimes taking a break can help. It sounds like if you see him "every day of your life" you might also be looking for a chance to take a break for a bit as well.
I have had friends that have fit in all three of these scenarios. I myself can be a whiner when I choose to. The best thing to do for a whiner is not to dismiss them, but do not let them rule you with their black cloud. They do not want your sympathy –Â*they want power over you emotionally. Do not give it to them. Give them the support to see their problems and the strength to resolve them, but do not fix their issues for them. They whine because they feel powerless; let them know they are powerful and they will stop whining.