BG in honeymoon, but still losing weight

Went through a few days of agony with new diagnosis of FD with current cat, Frady, 14 years old. He has recent history of pancreatitis, and long term (3 years) of IBD, treated with low-dose (5 mg day, split) pred. Vet upped dose to 20mg during pancreatitis attack for 8 days, plus Clavamox. He developed ongoing diarrhea (2 mos) from the Clavamox that defied resolution. I should have realized there was more to it.

Finally went to Vet ER as he was failing big time one night. I am familiar with FD through another cat 20+ years ago. Things have definitely changed for the better. No monitoring back then--only urine. But having given the injections etc, I am at least not a newbie. Also administered and monitored my my mother's diabetes. Now finding the sweet spot on the ear has been challenging, but we have shouldered on (perhaps not to Frady's satisfaction, but okay.) Hope to improve on that with more videos and practice.

Initially Emergency Vet's recommendation (good guess) for insulin dosage 1 unit x 2 (without curve) based on Frady's initial BG being at 477. All other blood work looked good. My husband didn't want to leave him at the ER, so I was willing to try the curve on my own at home. However he was not eating or drinking on his own at that point, so we had started force feeding. Also, he was very weak and wobbly in hind quarters (I presumed neuropathy )

Insulin dose worked well the first day and night. The next am 1 unit was WAY too much and he was crashing by that evening, although he seemed to be doing super well BEFORE the am dose. Gave syrup and food, but he just went downhill fast anyway. Back to ER. (By the way, the ER Vet was well versed in FD and open to all processes.). She kept him 32 hours, ran curve, syringe fed all day and night, fluids given. Very good care. On curve she only administered 1/2 unit and lowest BG was 65 for one hour. BG stayed in normal range for the rest of the curve. We have not had to administer insulin since then--58 hours later still in normal range with 130's to 140's. Must be in honeymoon. Still monitoring twice a day. All good except he is STILL losing weight. Has finally started to self feed some, but not taking in enough calories. ? Trying for 250-300 cals a day. Back to force feeding again, but that just kills his appetite to self feed. Pushing the low carb food (Fancy Feast Classic) but he's still dropping weight rather quickly. He was raised on dry food, and definitely prefers it. We have tried several times to stop dry entirely in the past, but he wouldn't eat enough wet to maintain his weight. Help! What is wrong here? Am I expecting too much too fast??? Trying too hard? Weight has dropped 2 lbs in last few days, 7 oz in the last two. He is tired and goes off to himself.

Side note--diarrhea has stopped with BG regulation. Whew!