I know it's a no-no, but a friend's son is doing an internship in a law firm and one of the partners has been asked to provide informal legal advice as a friend in a very specialised area of the law where he is not fully competent.
Of course he shouldn't really touch this with a barge pole, but he's prepared his advice and he's looking for the best wording to put at the end - basically to say this is provided as a friend and I urge you to seek properly qualified counsel specialising in the area before you act on it.
In French he would put "j'insiste sur la nature amicale de ces conseils". Is there some kind of formal wording in English that he could use?