My DM (late 80s) was showing me her bank statement and I noticed the energy direct debit was £140pm. She lives alone in a large (3 bed) well insulated bungalow and I encourage her to have the heating on for 18 hours a day for about 7 months of the year - I get an email alert if her heating drops below 18'C.
Would you ask to look at her energy bill to see if it could be reduced by changing tariff, or is that being a bit rude and intrusive and taking away independence? She can easily afford to pay it, but I'm always looking at how to save money for myself and it seemed like a lot for one person.