Zignature, wet or dry, presoak the dry food and add water.
However, at age 16, the ailments you describe are most likely age related.
Food can only do so much, some seniors need a bathroom break about every 2 hours for optimal results. Minimum, every 4 hours.
Feed 3 or 4 or 5 small meals per day with water added, rather than 2 meals per day. Always have fresh water available. Don’t expect the dog to hold his urine all day, that’s how bladder stones develop.
Talk to your vet about prescription meds for the arthritis pain, care and comfort.
