One of my cats (just turned 3) seems to lose condition around this time of year. He suffers with furballs and goes right off his food. Anything he does eat is brought back up almost immediately. He's on a special diet due to risk of urine crystals, has wet and dry food, doesn't seem to keep anything down. Usually grass and/or fur brought up along with his food. He's lost some weight but not skin and bones yet.
Any ideas how can I keep him in good condition during this time? I do comb him and he happily takes the Katalax I offer him every few days.