How is she feeling overall? I never required HRT other than treatment for vaginal atrophy. My periods waxed and waned for years then stopped 21+ years ago. Initially I had itchiness which didn't continue although occasionally I get areas of my skin that is really annoyingly itchy due to loss of oestrogen.
Whilst HRT can protect bones and heart, I personally don't see the point in taking any medication unless symptoms are over whelming. Because I feel OK I never consider that I should ask for it.
Whilst going through school we had lots of exercise: hockey, cross country, which is good weight bearing to protect bones from an early age. Also we ate a wide diet including dairy. MayB she should think about her overall diet whilst growing up as well as how much exercise i.e. cycling, walking, swimming, jogging ...... because many schools sold off fields for buildings!!! = less access to sports. Plus the inclination not to eat dairy

Perhaps look at your diets and make notes for 3-5 days/nights: food and liquid intakes. Is there anything that you could gradually alter/improve upon?
Hobbies? Exercise? Cooking together ?
Brain fog may simply be general aging. The 'what did I go there for' scenario which is within normal limits for most of us!