Questions on feeding a wether sheep

I bought a wether sheep about 6 months old, had a horrible case of BPW and coccidiosis. Got him dewormed, ran fecals and he's gtg now. He's just super skinny. He has pasture and orchard/timothy hay. I just want to get him to gain some weight. I'm scared of him getting stones, so I don't feed grain. Any recommendations would be great. We have ewes, and they get small amounts of grain pellets once a day.

Good pasture and hay are the best. You can get alfalfa pellets that make a good supplemental feed/treat that isn’t quite so rich as grain.

Hay and pasture should do most of the job.
If we're trying to put weight on someone quickly, we feed them some alfalfa (soaked alfalfa pellets work well) with sunflower seeds and oats. If you don't go overboard with the grain, they should be perfectly fine. It can take a while before you see big differences, so be patient.

Thank you so much!