"We requested that he give us assistance."
This should be read as a reported speech, right?
If not, why "he give us" ? not "he gave us"?
The actual words were possibly, "Please give us assistance" (or, "Please help us".)
A request can be reported with a "that" construction with a present subjunctive form of the verb (that is why "give" does not end in -s: We requested that he give us assistance.
We could also report this as: We asked him to give us assistance.
If the actual words were, "Will you please give us assistance", we could report this in either of the ways already mentioned, or as: We asked him if he would give us assitance.