回複 asked a dermatologist, answer inside

This is "eczema", he needs topical steroid like clobetasol ointment , over counter hydrocortisone is too week to clear it. If he has trouble to get medication here, he can wait until go back to china, this is a very common skin problem in elderly triggered by dry skin and dry weather, but nothing severe, no infection. Let him stop scratching which can even worsen the situation.