Send the Holy Spirit.
Remember that the Holy Spirit is the Counsellor, the Comforter. When you can't get through to someone, the Holy Spirit can. What you say to someone is screened by their mind. The Holy Spirit has a distinct advantage; He reaches the heart.

Do you give up? Then step back. Take hands off. Send the Holy Spirit!

For example you can pray like this:

"Father I can't reach (name.) I am going to let you speak to them. Their mind is closed to me; but you can reach their heart. Your Spirit leaps over mountains and bounds over hills, The Song of Solomon 2:8. No barrier is too big for you. So, please send Your Holy Spirit to (name) and you tell them what they need to know.

I am going to take my hands off. I am going to leave them in your hands. I am not going to keep trying to get through to them until you show me that the door is open."

“Pray as though everything depended on God. Work as though everything depended on you.”