Is Lisinopril The Best Treatment For HTN Control ?

Inquiring for a sweet friend who has had several failed parathyroidectomies. Both her serum Ca and PTH are still elevated. She s not a candidate for repeat surgery, and Sensipar has made her too ill twice. so it s been DC d. In the meantime she s been put on Lisinopril, also a second time, for HTN control (causing her to cough, but continuing to take...). Each time she has gone on the Lisinopril it has lowered her PTH, although her elevated total Ca stays the same at 10.7. My question is..... Is it a coincidence, or could it possibly be because of this drug s unique ability to decrease proteinuria? Thank you!