It is, perhaps, the same monk who is mentioned as Saddho (v.l. Sandho) Kaccāyano. (S.ii.153, Giñjakāvasatha Sutta). He asks the Buddha a question on the elements (dhātu), and the Buddha explains it to him. In neither case does the Commentary say anything about Saddho (or Sandho).
The translator of the Saṃyuttanikāya regards saddho as an epithet.