In the past, my sister was able to cure cases of bumble foot by coating the foot (after careful washing with soap and water) in Desenex cream or other anti-fungal cream and wrapping in bandages. She used gauze and masking tape as a bandage. The chickens didn't tend to try to remove it. Bandages changed and cream reapplied until the infection went away. A problem as severe as the one pictured seems to indicate a lack of general health - poor diet maybe - and/or unhealthy housing conditions.
Heavy scalyness is usually due to mites. This is really easy to fix in chickens by simply providing them with a dust bath of diatomaceous earth. I use a large litter box filled with a few inches of the DE.
Unfortunately, I agree with you about the euthanasia Roger - this has gone too far and the poor bird may never recover without antibiotics and an awful lot of TLC.
Burra Maluca, if your friend only has a few chickens and plenty of time then she can cure both of these problems as mentioned above but something has gone badly wrong with the conditions the chicken has been kept in and if it were me I'd spend my time making sure the birds' housing and exercise yard are dry, big enough and with lots of straw or something to soak up the birds' droppings.
OK, I've been in touch again and passed the info on. Apparently they bought the chickens at a local market and have already lost half of them with some sort of parasite infection - it sounded like lice from the description. And since the photos above were taken, those blisters have started to burst so it doesn't sound too hopeful for poor Pui-Pui.
Thanks for the advice everyone, and I'll let you all know the outcome. Hopefully she can save some of them and prevent any future chickens developing the same problems.