It is not permissible for your sister to ask him these questions as she is non mahram to him. Ask your wali to approach him with these questions instead.

I’ve intended to ask one of my sisters to ask a brother some questions for me regarding his interest in marriage and also about some conditions that I have. Can I do this?Sheikh, if I get my answers and then in sha Allah I will not tread in that path again and I’ll move on.It’s just for self contentment. May Allah reward you.