At age 21, kidney transplant should be the treatment of choice for your niece - quicker the better. Long term haemodialysis always carries the risk of hepatitis B and C and outcomes of kidney transplant charges if one of these infections is acquired as well as the longer the patient is one dialysis. So I would recommend to hasten the process of looking for a blood group, compatible donor in the family- parents, uncles aunts 18-60 years of age can donate.