I agree with you Mart, from the description of your neighbour's plant it could be the same problem. Steaming the soil did not solve the problem too and yes it could be a problem of the soil itself. I forgot to mentioned that I used Epsom salt too and it did not help. Back in 2014 April I had beautiful peppers growing in my garden if you can remember. I could not find the post but this is the photo from my garden in Garden Stew I had a total of 3 plants then and I did not had any problem with them. The only difference is that now I planted them in the back part of the house and before they were planted in the front. Did your neighbour managed to solve the problem?