Fred sounds like he may have ADHD. I'm Fred and I have ADHD. Now I'm not an expert so it's not necessarily true. ADHD comes in a spectrum of severity, and plenty of ADHD symptoms are just things normal people have trouble with too.

That said people with ADHD tend to have trouble with delayed gratification. Helping your coworkers has immediate benefits when they are grateful for your help, even though long-term it may make things worse. We also tend to have a lot of social anxiety and care a lot what other people think about us (rejection sensitive dysphoria). For these reasons, I believe people with ADHD have learned to be very helpful to those immediately around us, even to a fault.

Fred still has to get his work done though. Have some empathy for him because you don't know what he may be dealing with compared to you, but it's not an excuse.