There are some options to make a loan in honor of someone:
1) set up a separate Kiva account in honor of that person (you or someone who is interested in Kiva would control the account)
2) set up a lending team in honor of that person and you could make a loan from your Kiva account and attribute it to the honorary lending team; others could be asked to join the lending team
Once the loan or the lending team is established, you would have to take the initiative to notify the target recipients that a loan was made on their behalf. The main problem in the scenario you described is having idle money after the loan is repaid, especially if the recipient is not interested in managing the funds.
You could contact Customer Service at
contactus@kiva.org and see if they have plans in the works to create a gift account option. If the person is not interested in managing the repayments, the default setting could be set to turn all repayments into Kiva donations.