The protagonist is an older man, probably in his 60's. He's a retired police detective of some sort, and he is also ailing physically. He lives in a nursing home, and IIRC is not physically well enough to undertake much activity. There are several moments of grim humor between him and his roommate. Both make wry jokes about having a new roommate if a surgery doesn't work out, etc.
The man is able to keep active, and assist his daughter (who is an active duty police officer) through an advanced technology that allows the surface of an object (in this case, a balloon carried by his grand-daughter) to be sprayed or imprinted with a sort of camera system. I believe it is supposed to be based on some cutting edge nanotech. The protagonist is able to see and hear and communicate through the system using a monitor or computer in his room. The only indicator of its presence is that an image of his face appears in the balloon when he's linked up to the system.
The current case his daughter is working on is investigating a local drug ring she believes is operating out of a local carnival or circus. She's at the carnival with her young daughter, who is not aware of the nanotech imprinted system on her balloon.
Much of the story reads more like a crime drama than sci-fi, other than the futuristic communications system, which plays a pivotal role in several scenes. IIRC, the protagonist is pushing his daughter to take risks, and at some point the grand-daughter might fall into the hands of the drug dealers.
I can't recall the ending, but I think it was a "happy" one of some sort.
Publication Details and Timeframe
100% positive I read this one in a sci-fi magazine. I'm almost certain it was published in the mid to late 2000s. Unfortunately, my Google-Fu has failed me here, and I haven't been able to find the story, despite the relative wealth of detail I can recall this time.