So foul brood can be transmitted through the honey then? What else can? I have heard that foul brood is a pretty bad infliction. And none of those are a danger to humans, it seems.
The only bacterium honey can carry that is dangerous to humans that I'm aware of is botulism, and only in quantities that could harm an infant or someone who was severely compromised in their gut health or immune system. This is why honey bottles often have a warning that says not to give honey to children under 2 years of age. The high sugar content of honey kills some bacteria/fungi through osmosis, but for others, like foulbrood and botulism, it just causes the microorganisms to go dormant and not reproduce, which means when they enter an environment that is favorable for reproduction, like the gut of a bee or human, they can awaken and get back to work.
As far as helping a single weak looking bee, as beekeepers, we don't worry about that. It's true that we brush a few bees away while closing a hive, but we treat the whole colony as a single unit and gauge it's health as a whole. We might as well try to water and fertilize a single blade of grass in the lawn. In a whole hive of bees, there are always a few struggling or dying bees. That's natural.
I know but apparently, a lot of people don't realize that. Another user did bring that up, along with the possibility that the bee was near the end of its short life. There seem to be a good number of people who will do what they can to save anything, including stuff that I just want out of my house, dead or alive.
The thing about honey bees is they will often leave the hive to die if they can, so they don't make more work for the undertaker bees, so more often than not, a lone struggling honey bee has already gotten her affairs in order and made her peace, and there will be nothing you can do for her. Now, the only major exception to that in my experience is if the weather was very warm in the morning, but in the evening the temperature quickly fell, and the bees became too cold to fly home before dark, and spent the night outside the hive. If these bees aren't on a flower, they just need a little honey or syrup to give them the energy to get to a flower or get home, and if I find a bee in this situation, I'll give her a drop of honey to get her going again. A bee like this will just be slow moving, because she doesn't have any energy. But visually struggling bee is usually too far gone to save anyway, and as Bob said, is nothing to be concerned about. In the summer, the individual bees live only for 6 weeks, so hundreds of them are dying every day.