<reH> and <-pu'> seem odd together here. As if he is always in a state of having already borrowed money. I can't say for the German or other translations here, but the French implies that he was always in the process of borrowing money, which would imply that a <-taH> might be better. But really I think the Klingon would work best in the simple aspect (he always borrowed, borrows, and will borrow money from me).

I see what you mean. I had the same thought. It really depends on the scope of {reH} and {-pu'}, is it reH(pu') as in "It is always true that it is always the case that he had borrowed money, or is it pu'(reH) in the sense of it being a completed event that he was always borrowing money.
The German sentence is like the French one.

There is but one sentence with {reH} from canon sources that has an aspect suffix on the verb:

DuraS tuq tlhIngan yejquv patlh luDub 'e' reH lunIDtaH DuraS be'nI'pu' lurSa' be'etor je. [sic!] «The sisters of the house of Duras, Lursa and B'Etor, are constantly seeking a higher standing for the House of Duras within the Klingon High Council.»

This sentence isn't really problematic as {reH} and {-taH} really don't cause a problem. I added [sic!] because it's unusual that the {reH} follows the pronoun {'e'} here. So that doesn't help us.

But there's a sentence where the English translation is "always" plus a past tense:

reH DIvI' Duj vISuv vIneH. «I've always wanted to fight a Federation ship.»

So this past reading really gets lost in Klingon. So I'll follow your suggestion and the pattern of that sentence and remove the aspect suffix.