One of our labs has been getting more and more infirm since Xmas. He's had different types of tablets to boost blood flow to the brain but they've had no effect on his general behaviour and dual incontinence. We love him to bits but are getting so downhearted about the changes in him which the vet has said are irreversible. He still knows us, eats and likes a potter on a walk but I feel so sad. When does one say that 'enough is enough'? 