the pain increasing day by day suggests you should rule out cellulitis
in the foot or a hairline fracture
of the metatarsal bones. Check if there is any redness
, swelling (compare with the other foot), tenderness (just touch and try to press gently over that area of foot and see his reaction) exist. If so then any of these two conditions is existing there. In case of cellulitis, a GP or Diabetologist
can prescribe appropriate antibiotics and anti inflammatory agents. In case of a hairline fracture, he would be given a palliative care
for a few weeks to help the bone to unite and he would certainly feel better with calcium and vit D supplements, if not contra-indicated. All the best.