Hello Massimo, I am a nutrition officer and not a doctor.
Thank you for highlighting the issue of infant formula in Afghanistan. It is really disheartening that the people mandated with promotion and protection of optimal breastfeeding are the same people wrecking it. I now understand why The UN states that “about half of Afghan children are not breastfed”.
The issue of health workers selling the formula seems to me like a classic conflict of interest case, although the code on breastmilk substitutes doesn't explicitly prohibit them from doing it. They may be taking advantage to make quick money. Its probably a lacuna in the The International Code of Marketing of Breastmilk Substitutes. However feel that the following phrase should be enough to deter them;
Health workers should encourage and protect breastfeeding ...
In crisis and emergencies, NGOs working in the area, the country ministry of health and other players in the humanitarian work are mandated with monitoring such issues, am not sure of the situation and players now. Contacting the UNICEF country office might give insight on the issue and offer possible relief , assist in contacting the relevant area officials and ensure a more protected infancy to those little ones.
In supporting the mothers, qualified breastfeeding support, assuarance on the mothers' ability to adequately breastfeed, social support and community-targeted health promotion on the issue might help. Cultural issues around the female anatomy and the mothers' nutrition status may also hinder breastfeeding and contribute to sentiments of 'inadequate breastmilk', here, the nutrition team in the area may be of support.
Note: If pre-crisis use of infant formula was prevalent, then artificial feeding would likely crop up. Previously, there were reported incidences of donations of infant formula which could also be a factor in the current problem.
( If you happen to follow up on the health worker issue, please lets know of the outcome )