Repaying a loan in a foreign currency

Q: Zaid is in Dubai. Aslam, from Pakistan, is in need of some loan. Zaid does not have a foreign currency account in Pakistan, so when Zaid transfers 2000 dirhams to Aslam, Aslam receives Pakistani rupees equivalent to 2000 dirhams. After one year, the Pakistani rupee value has dropped, now will Aslam return the same amount 2000 dirhams or Pakistani rupees that he received a year back? Or should he return the rupees equivalent to current value of 2000 dirhams?

Advance Payment Guarantee

Q: We are in the construction industry and we use a contract known as an Advance Payment Guarantee and I want to know if this is acceptable please.

Basically, we pay a large percentage of a subcontractor's scope upfront. A third party acts as a guarantor that if the subcontractor fails to deliver (either works or materials) they will pay us back what we have paid upfront.

Please advise if this arrangement is acceptable