I am a divorced 15 years before my husband a...

I am a divorced 15 years before my husband a national of uae. Igot a custody of my son but he refused to give me allowance. &my sons passport with him, if I want I can ask the passport through court,as I asked for once to travel abroad &return back to him in year 2006. Then after that I never got my sons pp. Nor his father's any news,now my son is 18 year old I need his passport. I went to court family guidance &reconciliation, they tried his phone no. When they replied they said wrong no. Then I started to search my sons father through his friends, they said they also not seen for more than 5, or 6 years. Then I tried in the area where he live . shops, neighbours, then started searching hospitals , at last I found him in hospital , he is very serious,can't see can't hear can't speak his condition is not good. But my sons passport is with his first wife and her daughter ,she is married .and holding my sons passport with her.(this two ladies created all problems, they are angry because i had a son , these was the main reason to divorce me. they are taking all the pension money houses all property with them.please I need your advice what to do, how to start the case.first of all , my son needs his passport , where ever he is going they are asking for original passport as for admission etc. Thanking and waiting to hear from you.