I am sorry to read of Spencers illness yet it is great that he is happy in himself. My Ollie was over 15 when he passed and I think being over 12 when he started to have diuretics( while not on heart tabs but other meds)
I knew he struggled with his toileting (urine incontinece) as such a clean boy it worried him - I spent so much time searching for the best ways for him to cope and myself to manage him. I was always concerned that urine can scald the skin and sores form, luckily this never did, so I hope this rather long read helps.
So at first he slept on old large towels at night with easy to wash doggy blanket and waterproof pad. So the blanket and towels were easily turned around by washing - then I found Glandarcy dog belly bands and bought 2 with four washable pads and these worked wonders at night and just needed soaking and washing each morning. As he worsened I went to either Simple Solutions or Amazon basics disposable male dog wraps, I only used at night and used the Glendarcy as a daytime choice. Then I found Tesco Free Spirit ladies pads (normal) would attach to the Glendarcy pad and life and washing got alot easier.
An ample supply of old face cloth/cut towels plus a little mild baby shampoo to clean away urine smell from fur.
But the disposable items as Ollie aged and got less mobile were worth the money and cut back on washing,
If I can be of further help just ask.
J