Short answer : theoretically YES, but this has to be a VERY GOOD friend of yours, but again, you might prefer to buy a used mac-mini
TLDR : You will need this Mac for a really long time, depending on your app requirements, your development skills, and your luck with Apple. For example:
- You might need some days to set up Xcode and the required SDKs and Libraries.
- It might take some time to get that Developer Account, sometimes you can wait too much even to get your request reviewed.
- When you submit your application for the first time, you will have to wait sometime, maybe up to several weeks, or even months, to get your app reviewed.
- Each time your app gets rejected, you will need to find and fix your issues (without much help from Apple, other that pointing out the guideline rule that you broke ), then re-submit your app for review, and wait again.
- Each time you try to apply a patch for your already deployed app, you will have to get your app reviewed and there is a chance that your previously legit app, now breaks a new guideline, so you re-submit and wait
So, from my experience the development of an iOS app is a very lengthy procedure, without even considering the actual code-development time. Can you borrow a Mac for that long ?