Is mano or mind function of brain? Then what we perceive is mere creation of brain If brain cease to function all phenomenon also cease to function as well.
Body including brain is so vulnerable to break up and Buddha emphasized that no one should cling to this body and its function to avoid all sufferings.
Evolution is truth and all religions are mere fantasy which originated from ignorance to the scientific findings. 
Everything which is brought about should perish in no time. That's the essence of Buddha's teaching(Dhamma).
The question "is mano or mind a function of brain" is irrelevant. 

There is a sense organ with the function of knowing what are called 'mental objects', namely, feelings, perception, thoughts, emotions, mental images, etc. These mental objects, unlike many physical phenomena, can last for merely a moment. This sense organ is called 'mano'. 

The sense organ also develops 'intelligence'; based on its experience of these mental objects, particularly in how these mental objects accord with or produce another mental phenomena called 'happiness' &amp; 'suffering'. Thus, from the accumulated experience of this "mano" arises "mental intentions" that produce actions (as described in Dhammapada verses 1 &amp; 2). 

Buddhism has its own view on the Indian term "nama-rupa". "Nama-rupa" in Buddhism means "mind-body" (as defined in SN 12.2). This term is used as a compound to highlight the inseparableness of mind &amp; body. Not only are 'mind' &amp; 'body' inseparable; but also the consciousness (sense cognition) is inseparable from this 'nama-rupa' (per SN 12.67). 

While "mano" probably functions dependent upon the brain, its role is "mental" rather than "physical". What is "physical" is explained in MN 62; in the paragraphs about 'earth, water, fire &amp; wind property'. 

SN 12.61 may help here understand the difference the 'mental' ('nama') &amp; 'physical' ('rupa'): 


  It would be better for the uninstructed run-of-the-mill person to hold to the body composed of the four great elements, rather than the
  mind, as the self. Why is that? Because this body composed of the four
  great elements is seen standing for a year, two years, three, four,
  five, ten, twenty, thirty, forty, fifty, a hundred years or more. But
  what's called 'mind (citta),' 'intellect (mano)' or 'consciousness (vinnana)' by day and by
  night arises as one thing and ceases as another. Just as a monkey,
  swinging through a forest wilderness, grabs a branch. Letting go of
  it, it grabs another branch. Letting go of that, it grabs another one.
  Letting go of that, it grabs another one. In the same way, what's
  called 'mind,' 'intellect' or 'consciousness' by day and by night
  arises as one thing and ceases as another.
  
  SN 12.61