I got a pretty sever concussion 2 years ago and since then I've been living with my by then recently widowed grandmother of 80 years old who's kind of an alcoholic with kind of a poor diet.

Ever since my starting living with her, her alcoholism has been under control and she drinks "only" about 600-700ml of wine a day, in three doses. Reducing it further seems unrealistic.

Anyway she used to have quite a lot of pretty strong neurotic fits over nothing and seemed to be very anxious about things. Having read up on various food supplements because of my concussion, I figured she might be deficient in magnesium and that trying to give her some wouldn't hurt.

I didn't expect much from it (I'm a fairly skeptical person, especially after learning that pretty much no supplement helped me with my concussion), but the effects of the magneisium lactate pills I bought her (0.5g or Mg lactate per pill (51mg of Mg), I've been giving her 3 and later 2 per day) seemed almost magical.
Her mood became a lot better and stabler, and she started thinking much more clearly very soon (~1-2 days) after starting taking it.

Anyway, I've been giving her those pills for several months now (about two times, she decided she'd stop taking them, and her fits came back so I told her no wine unless along with an Mg pill). The label really says it should only be used prophylactically for 10 days and longer use should be consulted with a doctor.

Do you think it is safe to keep giving her those pills?