1) When counseling a Muslim of the opposite gender, it is recommended for a mahram or family member to be present during the session. What happens in the case where the Muslim client doesn't feel secured to disclose his/her problems in the presence of a third party?
2) In a situation where one can't find a female counsellor, how can a Muslima who needs counselling go about it?
To prevent khalwa (seclusion) a third person might be present during counselling. However, I would not recommend this as it defeats the very purpose of counselling- the client might feel uncomfortable sharing certain issues in the presence of another. Thus, the best thing might be to visit a counsellor of the same gender.
As Muslims, we should try to get the best possible support, keeping in mind the limits of the Shariah. Thus, if a female counsellor isn't available, the Muslima might visit a male counsellor.
However, with the advancement of technology, online counselling has caught up, alhamdu lillah. IOU offers Islamic Counselling with a female counsellor. The Muslima can opt for this option if she is interested. Here is the webpage: here: http://islamiconlineuniversity.com/counseling/counsel.php