Hi Rarsweet: He would probably need a neurological evaluation to find out. It could be related to a car or sports injury he may have had during his lifetime, or he could have some neurological condition. Several situations are possible. The BPD behaviors and the slow movements may or may not be related in any way. The speech pattern could be related to states of anxiety or stress. There are several possibilities, but only a medical professional could diagnosis it.
You might find the articles at the links below interesting. If you drill down into the first article, there is mention that veterans who have had head trauma, are more apt to exhibit BPD behavior. The 2nd article relates to possible causes of movement disorders.
www.sicotests.com/psyarticle.asp?id=449www.neurosymptoms.org/#/movement-disorders/4533053142