Thx for the pic. It's so stretched I can't tell what it is. Sand just clogs drainage so unless it's very coarse, best to be avoided, certainly such fine sand. I'll let others address it better than I, but indoor window sidelight & outdoor light aren't comparable at all. Yes, agreeing that plant is starved for more light. Still, even if in succulent mix, that soil needs amending to be faster draining.

Is the soil wet? If it is (wet), pull the plant/soil out of the pot and expose it to the air. If it's /dry/ then take it to the sink and fill the pot with water and wait for it to run out the bottom. Tell us what it does, does it go around the edges and almost immediately exit the bottom holes or does it seem like it's taking it a while to exit?

I don't think succulent rot usually presents itself in dried up leaves. In my experience, it's usually shriveled leaves that rapidly turn yellow and fall off, and a blackening stem. Also, the placement of the dried leaves isn't starting from the bottom of the stem and working upwards, it's in the leaves that are exposed to sunlight. So, I don't think you need to worry about rot. Looks like these guys are shocked and sunburned from the sudden change in environment. Succulents need time to adjust to bright, direct sunlight, especially when you buy them from a store that keeps them indoors where they're getting little to no sun. Gradually give them more and more sun each day for 2 weeks until they're properly acclimated to the amount of sun you'd like to give them everyday. The change in temperature from a cool air-conditioned house to a warm/hot outside could also have contributed to this blanched appearance. Overall I think your semps look pretty healthy, other than the dried bits! You can probably just pluck those leaves off, if they bother you.

Your sempervivum looks OK, only a bit lacking in light. They can be grown indoors but they need a lot of sun. Your semp has flowered and you are seeing a normal flower stalk. The main plant will now die, leaving the pups around it to continue the plant. You should cut the pups off and let them root as separate plants and repot one back into the pot, otherwise you are going to be left with a gap in the pot and the pups hanging outside. The other one is an echevaria and also showing a litlle lack of light. You can cut the top off it, let it heal for a week and reroot it before planting it back into the pot. Otherwise it will have a long stalk with leaves at the top from now on. Give them as much sun as you can from now on.