I left my apartment for a month and took some of my plants with me. I left him behind, because he seemed to not like that much water. Now he looks dehydrated and part of his stem looks burnt. Wanted to know what kind of succulent he is to better fit his needs.
I think it is a member of the Crassula family (genus). The most popular member of this family is the Jade plant (Crassula ovata), but I am not sure if you have the same species here. Your plants seems to have a more lighter green than the Jade plant.
Succulents like Crassula, don't need a lot of water. The soil can dry out between waterings, let's say give it once a week or every two weeks some water in summertime, and reduce it in winter to once a month or every 6 weeks. It also likes a lot of light, but let it acclimate if it is not yet used to direct sun light.
It looks like a Pachyphytum and less likely an Echeveria (Members of the Crassulaceae family), but possibly this is a hybrid. I don't think it may have such a long stem, possibly too little light. A jade plant (Crassula Ovata) has a different stem and leaves.
The one in the middle appears to have a basal stem rot. That's why it looks "burnt". Cut it above the rot, let it callus and repot. Does the window face the sun most of the time? If you acclimate it to full sun (Gradually), you may get a more compact growth and different leaf color (More bluish-grey powder). Possibly that will give a much easier identification, as the plant may look as it is normally sold at nurseries or growing in the wild.