Get the x rays reviewd by orthopedician, if freacture is non-united or in delayed union,then it means there is some distraction at the fracture
site,or interposition of fibrous tissue at fracture site.If osteoenia has developed in the local area it means decalcification of bone , but there may be no osteoporosis
in other bones of body, which can be confirmed by x ray of pelvis,spine or bone densitometry
probably he would need bone grafting
at fracture site along with New kind of plating called LC_DCP with locking screws in osteoporotic bone to promote callus
and maintain stability.
Tens is for muscle -nerve stimulation but it will not work for non-union