I can only speak from the respect that I was an activity director at an assisted living facility and an occupational therapist working in geriatrics. Typically we encouraged visits from young visitors to our residents. You dont mention the extent or living situation so its hard to say. The residents very much enjoyed visits from children playing simple games, coloring and similiar activities.
Has your uncle mentioned exactly why he thinks its not a good idea?
Just wanted to mention that it is very hard on older children that had a significant relationship with the person. They expect the person to remember them and when they dont its very upsetting. I understand your son is younger, but just for anyone else reading. It can be quite tramatic.
DX: CRPS, Fibro, CP, DDD, DJD, Syringomyelia, Arachnoiditis, failed fusion. Fusions C5-6, L5-S1, hardware removal and removal of scar tissue. Gastric Bypass 8/11, SCS implantation 7/12