I hope your DD recovers quickly.
Besides the safety angle, there are also a couple of other reasons to turn down the water heater. Feel free to use these as ammunition against anyone in your home who's resisting the idea of lowering the hot water heater temperature.
First, as a matter of efficiency: While it may seem that mixing equal parts 150F "hot" water with 50F "cold" water to get 100F water would be just as efficient as just using 100F "hot" water straight, the reality is that the latter is a lot more efficient, because even though hot water heaters are insulated, and perhaps super-insulated, there is still loss. You should set your hot water heater so that you use mostly heated water; such that you have enough, but only just enough hot water.
Second, as a matter of reliability: There is a component of your hot water heater, the sacrificial anode, that helps extend the life of your hot water heater, by forestalling corrosion of the tank itself. FWIR, the hotter you keep the water in the tank, the quicker the anode degrades, and the sooner you have to replace it (or if you don't replace it, and most of us don't) or the sooner the tank itself corrodes.
One way around both of these concerns is to get rid of your hot water heater and replace it with a tankless water heater.