Hi Mrs Tiggsy, love the name. Health insurance is no longer compulsory for over 65's to obtain residents permits. Private health insurance will be expensive at your ages (we know being oldies) and may not provide the cover you need at an affordable price.
Your other options are to join the Turkish Health Scheme - SGK, but be warned once you join there is now no option to leave it unless you surrender your RP and leave the country or die. The premiums increase twice yearly and are currently around 285TL per month each, so not cheap either, close to 7,000 TL for you both for a year.
My advice, hindsight is a wonderful thing, is to keep a UK address and return there if/when your husband needs his pacemaker replaced.
We didn't keep a UK address but wish we had. However, having said that I have just had an angioplasty and stent done here, Antalya, with RP but no insurance it has cost me around 12,000TL. You pays your money and takes your pick, good luck with your planned move.
Sorry can't help with the dog question.