Radhika can easily ask Barkha to sign on the Transfer of Property of Purohit family in her name, in front of family and specially Dev. Barkha will not be able to deny, coz if she does, her real face will be exposed. This way Radhika will get back the property.
Secondly, according to Dharm, ppl recognises Barkha as Dev's wife and due to property papers, even law does the same, to nullify them, Radhika should convince Dev for a court marriage silently, thus putting Barkha in a tight spot in the eyes of law also.
They can also talk to the lawyer personally and explain him silently the situation and try to put him in their team. He can re-make the papers and ask Radhika to sign on them, so that tmrw when truth comes out, RaDev can be rest assured to be rightful in the eyes of law.
Radhika can also accompany Dev and Barkha everytime and anywhere they go, proclaiming herself to be the personal secretary of RP, and hence places where RPian is not requried, there also Radhika can accompany Dev, that too no one questioning her about her and Dev's relationship.
Radhika while accompanying should take keen interest in all the works of RPiti and openly give out her views in front of all. Radhika is shown to be a strong person and a person who solves even the toughest probs, so after a few decisions itself, Mahants will start turning their heads towards radhika for suggestions.
If Radhika does all these work, then Barkha will not get lone moments with Dev to fill his ear and also when the truth comes out, ppl can think abt the positive points also b4 negating RaDev from RP post completely and also not point fingers at Dev's and Barkha's relationship and character at that point.
Your 2 cents plz...