Firstly they are married, sorry meant to mention this earlier.
Okay they went their separate ways years ago but I guess about 20 years ago when Dad bought first guest house. His property is valued approx. £220K, Mams about £95k, no mortgage on Mams definitely, or Dads as far as I am aware. Mam has £500 a month not sure Dads income. Mam and Dad's ages are 80 and 82. The question is aimed at if they divorce which looks likely
At preaent it amounts to about £2,100 a year with mam paying for ALL other outlay eg £3,000 recently for new heating system