"I went independently to ask about doing a root canal on the tip # ***** and add a small build up in the hope that it makes my dad have more biting power. "
It is unlikely that this tooth would add any functionality-- either on its own, or in the context of a lower partial denture. The tooth is not only structurally deficient, but it also has too short a root to contribute to bite or denture stability.
"The endo dr showed me that my dads bite does not allow his upper gum and his lower teeth to meet up."
Teeth do not "meet up" when they only occlude against a toothless arch. If the intent is to create a functional occlusion, your dad will need an upper prosthesis; anything short of that will not create a workable bite. I am skeptical whether the removal of the lower teeth will either add or detract from functionality, and I would be inclined to recommend the retention of any lower teeth whose status merits the effort unless those teeth are inflicting mechanical injury on the upper gum-- especially if the fabrication of a lower partial denture is fabricated. That presumes that the teeth can be properly restored and the decay eliminated.
"If he got all his remaining teeth pulled, I am back to having concern for his emotions and weighing where he is at psychologically."
I am unqualified to comment.
"Do you think there is periodontal disease in the current xray? The dental hygiene yesterday said he did not have that much tarter."
A diagnosis of periodontitis is made using multiple criteria-- some of which are unavailable here (presence of tartar is not one of them). Except for the bone loss in the bifurcation (the area between the roots of tooth #19), there is little evidence of active disease. There is one 4 mm pocket on the distolingual of tooth #29, but that barely qualifies on its own as meeting the diagnostic criteria of periodontitis.
"I am curious if my dads tooth had gotten better once it was filled and that dark image at the roots had cleared up as per the recent xrays compared to the panorex done in aug 2015."
I assume you're referring to tooth #19. No, it did not get better, and the placement of a restoration on a tooth with active endodontic infection would not have been expected to "clear up" a loss of bone in the root bifurcation area.
Hope this helps...