At 15 years old, Lenny has lived a very good life due to your love and diligence in caring for him. If he feels better on your homemade suppers, then I say more power to you both. He is at the age of diminishing returns when it comes to treating health problems. Love him, feed him what he likes, and when either he quits wanting to eat or quits being able to get around, seriously consider helping him move on. Our Cardi Duncan lived the last three + years with arthritis (two daily drugs for that), diabetes insipidus (eye drops twice a day costing an arm and a leg), synthroid for thyroid. He lived to be 15yrs and 7 months, over 2.5 years longer than the UK dog mortality suggested was average for a Cardigan Welsh Corgi. Ultimate decision to help him on was because we could no longer keep him comfortable with the arthritis. We'd had him for way longer than expected and it was the last and greatest gift we could give him, a gentle death being touched by my husband and I who adored him and his vet who'd treated him since before he was born and who wept as she put him to sleep. Hope Lenny continues to thrive on your own diet and whether you measure the time he has left in months or years, enjoy every minute of it. Thinking of you both!