My mother has high levels of pth low vitamin d, normal creatinine and elevated levels of urea, what does this mean?

Vitamin D deficiency. Vitamin d deficiency can result in increased secretion of parathyroid hormone which attempts to maintain a normal serum calcium. Correction of the d deficiency should result in a normal parathyroid hormone level. High urea could result from dehydration.
Low vitamin D. Can lead to higher PTH levels, which should normalize w/d replacement. If not, need to look for other causes such as a parathyroid adenoma or benign tumor of the parathyroid gland. Also make sure she is not receiving hctz (hydrochlorothiazide) diuretic, which can increase pth. Calcium needs to be checked, and if BUN is still high, she may need better hydration. Check w/doctor about her renal status.