make sure you do it.I nearly got in trouble a year back when i forgot to carry NOL.The guys in Nepalese immigration will try to give hard time and take money from him.Most of 'em will try to do that.
I got lucky coz when i was about to get in trouble one of the nice guy around  who worked there let me go though i didn't have NOL.
Ask your brother to have one to not have any hassle during the last hour.