he is indian citizen, and Indian passport send outside anycountry its not advisible even Indian citizen staying in the UAE.
if RPRF request for passport submittion will come then how he submit it, there are 2 ways only 1: in person get visa of UK and stay atleast 15days there might be it will costly for him or 2: send through some authorised person.
if he applied in ND he is indian citizen then no requiered visa, may be he have home in Indian so it will not costly to stay for him atleast upto getting visa stamp on passport.
Thats why I suggest him a ND. even I marked ND is faster then London CHC not only difference for 3months , if you look overall agerage in this forum London CHC is some slow thats also fine but problem is passport submittion for Indian citizen.
OMM