Yes you can if you have his details just use them on your mobile device login. You can either stream or download, the download expires after 48 hours though.
That pairing of your Dstv smart card to the mobile one is just some how to me. I once downloaded the mobile app, I was lovely being able to view what they all the details although there are some limits one can go. I learnt that can download movies from there, I was happy only to notice that you have to enter or pair your smart card number to that of your mobile. To I would have suggested that anybody that wants the mobile own can sub although I don't know how that pairing of the smart card number works whether the person has to pay more. If not then I think the pairing is OK.