Why is my dog being so clingy?

My dog who was always mainly my moms dog stopped eating and had to be put on IV feeds when I went away for a week, she does this every time I'm away for a few days, she's gotten more used to it but she won't let anyone near her until I'm back, it doesn't mean anything is wrong with your dog, in experience they try to make up with lost time and while they can't use reason, they appear to blame everyone for your leaving, try walking him a little more than once a week with your other dog and give him plenty of fuss but also put your foot down, if he growls at your mother or other dog, send him out of your room or tell him No in a strong but not yelling voice and leave the room, if he doesn't growl when someone enters then fuss him lots, if he continues then perhaps talk to a behaviourist, there may be more to you leaving changing his routine or something in his life that clearly upset him greatly, it may even have been the more frequent walks, try taking him or letting your mother take him every other day again, he may have enjoyed that routine and it's messing with him now.