LLLT laser cap plus Finasteride for my 75-year-old mother with thinning hair?

There are many treatable medical causes of hair loss.  Your mother should see a doctor for an examination to find a possible cause/ diagnosis before considering any treatment options.Laser therapy may be safe, but it generally does not work for hair loss.Finasteride is not generally recommended for women.

Low Level Light Therapy (LLLT) has enough basic science and clinical research to justify patients using it but data remains lacking on the ideal number of light sources, light wavelength, frequency of use, duration of use, and efficacy.There is no harm in your Mum using LLLT but no device has been proven yet to be better than another.At 75, your mother should probably consult with her family doctor before starting any medication.Has she considered camouflage products?

It's nice of you to try to find information to help your mother. I'd strongly advise you get a diagnosis first. There are dozens of causes of hair loss and you won't be able to tell them apart very easily (they can all look the same)For example, androgenetic alopecia, sensecent alopecia, fibrosing alopecia in a pattern distribution, lichen planopilaris can look identical. Drug induced hair loss can also mimic sometimes. Treatments are all different. Low level laser is safe but chances of success may be low or close to zero depending on the precise cause. Finasteride is unlikely to have much benefit in a 75 year old woman with long standing genetic hair loss. All in all, be sure to include and expert evaluation as you continue your research and helping your mother.