It depends what system you were looking at for the delta. In general, the delta will increase toward 1 for a call option when the stock price rises and it will decrease toward -1 for a put when the stock price falls. Some systems show the delta as a positive number all the time and just assume that you will know if it is a put or call option.

On poweropt.com, we show the delta as positive for call options and negative for put options.

So, if you friends position was a positive delta and getting larger as the stock price rose, I would think that is a long call position.

Since the positive delta was getting larger for a decrease in stock price, that would mean it was for a put option, I am not sure if you could tell that it is short or long, unless the provider you were reading shows positive deltas for short puts and negative for long puts. I have never heard of this before.