Michal,
Calling him is up to you, but honestly I would love to hear from him himself. On another thought, maybe him finding out that his extreme generosity has really done it's job and maybe, just maybe he'll reconsider getting back into flying. He is missed around here. I know of at least 5 members that have asked about his whereabouts recently.
Now as I mentioned what you do with the plane is completely up to you. It would not hurt a beginner and I can think of one plane right now that is a trainer that has no dehidral (the World Models SkyRadier has none or very very little), plus reconverting it back to a trike is not hard at all

. The Skyraider flies very well for the high wing trainer and is quite aerobatic to boot
Again, I'm not trying to tell you what you should or should not do, that is totally up to you and I personally would never try to tell anyone what they should do, it's not my nature, but I will make suggestions if asked and always mention my wishes.
Of course I just would love to see it get back to someone in need and I talked to you enough privately that I have no doubt that is going to happen. I am glad you are enjoying it and my guess is if you do call J3FAN, he may even enjoy hearing about what you are doing.