Hi Jelinda. Those are some very nice plants to grow in memory of you friend that passed away.
Would you be able to get us a sharper/clearer photo of the plant that you think is a sedum?
The lower part of the Donkey Tail stems looks to be damaged. I think you would need to cut that part of the stem off, up to healthy tissue, let it callous over for a few days, then replant it. They have about the same water requirements as your sempervivum, if over watered they will rot. The DT should root easily once the damaged stem is removed.
Give it bright light but not direct sun, your summer sun might be a little to intense for it.
Even the little leaf segments will form roots when they fall off the parent stem. Just don't over water.
