[Suze65]

Firstly, welcome to the forum, and I'm sorry to hear your tortoise isn't well. It would help us if we knew what species of tortoise you have, you can post a picture after you have done five posts, you will need to upload your picture to a host site first, like photo bucket, then copy and paste to here.
Could you tell us a bit about how you are keeping your tortoise, is he in an open top table, and what sort of substrate is he on. As for diet, Mediterranean species, need a diet do natural weeds and flowers of the right kind , not the type of food you have been giving him. He also needs calcium suppliment and vit d supplement for strong shell growth, and strong bone growth. Baby tortoises, need to be kept well hydrated with regular baths and available water, and a humid hide. They also need to be provided with a uv light and a basking light if they are in and indoor enclosure, and when the weather permits, to go out in the natural sunlight as much as possible.
So it would be useful to know the details of how you are keeping him, then we can help you.