Visiting Bhutan-Late Oct-7 days

Hello,

We are a Group of 3 adults planning to visit Bhutan late Oct (20th onwards) for 7 days. I%26#39;m really concerned about what the weather may be like, since my mother is a chronic asthamatic and if its too cold then she may not be able to visit.

Could anyone advise me on what weather we should expect (Deg C). Also, what would you suggest we do in the 7 days? Are there specific MUST visit places.

Any help would be greatly appreciated.

Thanks in advance

Sam