The following is relevant if either you or friend speaks English. They are some guidelines for learning French from the scratch based on my experience. If neither you nor your friend speaks English I will edit my answer in order to include French to French sources (FLE: français langue étrangère).

First of all Internet offers a plethora of options. To name but a few (all free):

BBC courses

Thoughtco

LawlesFrench

ToLearnFrench

They provide everything a beginner should know.

There are many great grammar books for beginners and Amazon is a good place to find used ones in affordable prices.

Personally, I highly recommend the book Easy French Step-by-Step, a best seller for anglophone learners of French, which has the advantage of a very reasonable price. The only drawback I see, is the lack of an accompanied CD for the pronunciation but one can certainly deal with it by watching French tutorial videos in YouTube.

Of course the aforementioned online courses also contain relevant material.

There are online dictionaries, but it is a good practice to have always available a hard copy.

One can find a glossary of the basic grammatical terminology (accusative, dative, personal pronouns and the like) usually in the form of an appendix in almost every grammar book for learning French.

The aforementioned appendices are most often accompanied by the French counterparts. I.e. Imperfect=Imparfait, Perfect=Passé Composé, Pluperfect=Plus-que-parfait, Past Historic=Passé Simple, Accusative/Dative=Complément d’Object Direct/Indirect, etc.

Of course, as always, Internet offers information about almost everything (glossary). But personally being a little archaic, I prefer the hard copies:-)! Thus, I suggest also a French Reference Grammar like that of H. Ferrar (Campridge University Press) which has the advantage of being irresistibly…cheap (used copy).

See also the discussion below

Please suggest any French grammar books

Recommended grammar textbook for self-study

Resources to verify French words, expressions, usage, grammar