Sounds like you've discovered what I call retrieval, helping those who get "stuck" after "dying." I have to put "dying" in quotes because the way most people think about what it is is so far from my experience of what it is.
It was nice of the old man to come back to thank you. So many times people like him are trapped in a way they they don't realize they are stuck until some one assists to guide them out of where they are stuck. I'll bet once he was able to move to a place where he could feel Love and perhaps communicate with is mom he understood what you had done. Brings tears to my eyes.
One of my interests in the kind of electronic communication that Keith's site here is about is to be able to open up more direct, conversational interaction between those who are stuck, like those who use to be in your house, and greater numbers of physically living people. There are many who are stuck for no other reason than beliefs, fears or expectations they hold about what death is. As you know from your experience with this immensely gratifying work, it changes you. You help them and in the process their existence becomes real to you. These kind of contacts can be life changing in the education we get from the experiences, and the knowledge we gain about who and what we really are. With electronic devices to communicate more and my stuck ones could be helped.
A big piece of this, in my opinion, is that the Instrumental Transcommunication devices people on this site are attempting to develop need an "energetic level boost" that comes from a person like yourself in order to more easily function. I mean, there needs to be a sort of "transducer" that brings the "deceased" persons' "energy" from the none physical world into the physical world so that the physical world electronic device can receive that "dead" persons' voice or image.
It's no accident that the Spiricom device development was done by a "psychic" (William O'Neal). He was in my opinion an actual and necessary part of the "circuit" that made Spiricom function to make voices of the "deceased" recordable with physical world electronics.
By the same token a strong skeptic in the presence of the electronic device can actually "block the signal" so the device can't work.
With your experiences that have shaped your beliefs toward acceptance of the reality of deceased peoples' existence, just your presence here at this website, talking about your experiences helps devices others are working on to function properly. These are just my opinions, but I hope you find this site one you like to visit and share on.
Speaking of sharing, have you discovered the Forums at http://www.afterlifeknowledge.com I think you might find the "Retrievals Only" forum an interesting place. It's the forum reserved for folks sharing stories of their experiences that you might find interesting. Some folks are novices who are just starting to learn and others are very experienced and willing to share their knowledge. If you see posts on that forum by "Ginny" say Hi to her from me. Ginny is a loving human being whose experience and knowledge and retrieval stories are great examples of how to handle various retrieval situations. I don't usually suggest things so "directly" but as soon as I started typing about retrievals here today Ginny just keeps popping up in my mind. And, folks on that forum will benefit greatly from reading what you might be willing to share of your experiences.
I'll get down off my soapbox now and just say Welcome again. People here well benefit from your presence as they work to develop their devices.