The rules require you to use a bit of common sense. You can argue bizarre interpretations along the lines of "the rules don't explicitly state that such-and-such isn't the case", but the intent is obvious to the vast majority of people. In both of your situations I agree with your interpretation, and think your friend is completely wrong.
Let's look at what ...
You could continue attacking as long as there is at least one soldier attacking your opponent's territory. Or you could choose to retreat, but that wouldn't mean giving up your turn. You could attack somewhere else, or move your troops to some other country.
You receive bonus troops for a continent each time you begin your turn in control of every district/nation on that continent, for as long as that remains true. That is, if you lose control of any district on the continent, you will not collect the bonus troops at the start of your next turn.
from Rules of Risk
In addition, at the ...