My dad's a diabetic and is experiencing finger paralysis. his fingers are jamming one by one, and then they go back to normal!

Needs med eval.: Uncertain as to the cause of these symptoms but it does warrant medical assessment.

Trigger finger: This is most likely trigger finger (also known as stenosing tenosynovitis, which is why people prefer the term trigger finger ;) It's due to inflammation of tendons or tendon sheaths. Diabetes is a major risk factor. See http://www.assh.org/handcare/hand-arm-conditions/trigger-finger for more info including treatments. Better control of diabetes will also help. See http://tinyurl.com/j6t4rlh