[Citroënbender]

I’d suggest a few things, they aren’t original but are reversible and aid safety.

First consideration should be a split circuit master cylinder. That will near eliminate the risk of complete brake failure.

From there, consider some aftermarket steel rims in 15” size. You’ll have to likely improvise fitting of the original type hubcaps but in return get a good choice of more modern tyres at fair prices.

The final change would be a disc brake and booster conversion, whether by adaptation or sourcing original parts. Sorting wheels as described above, will allow this without physical interference between brake/rim. People who haven’t experienced drum brake fade (with heat) may not be prepared for it when problems arise - hence the idea of fitting discs.