Hello
https://www.bbc.co.uk/news/uk-35552289
I always recommend to people to plan life well in advance. Major decisions, such as immigration, have to be taken in consideration as early as possible. Don't wait to be 70 and in urgent need of NHS treatment to start looking at it.
The main issue is to demonstrate earning/saving:
https://www.gov.uk/uk-family-visa/proof-income
For UK Citizens who live in high earning countries such as Germany or Switzerland, it's usually much easier. There is no absolute right to bring a partner/spouse in the UK [The immigration policy is the same UK-wide. It doesn't change if you are Scottish].
Do they have any other revenue? Or any saving?