I am afraid as since the remaining of your siblings have their own home, prima facie, you may not be able to get reverse mortgage loan as only one of you has used it as your Primary Residence, which is the primary requirement of being eligible.
However, the best persons to tell you if there is any way out (though I did not find any) would be to speak to your HECM Counselor online at https://entp.hud.gov/idapp/html/hecm_agency_look.cfm or by calling at(NNN) NNN-NNNN
The http://portal.hud.gov/hudportal/HUD?src=/program_offices/housing/sfh/hecm/rmtopten will serve you as a great reference.
Let me know if this helps...
Let me again make it simpler. As I mentioned in my original reply, the best person, who would be able to answer your question would be HECM Counselor and you may reach out to him to the link provided https://entp.hud.gov/idapp/html/hecm_agency_look.cfm or by calling at(NNN) NNN-NNNN
What I tried to convey that primarily, you all may not be eligible for reverse mortgage as only one of you have used the home as a primary residence.
In absence of any further details of your siblings and their current home, It is best advised to talk with the HECM Counselor along with help of a professional attorney who will find out some fine prints to make you eligible, which in my opinion would be difficult as we cannot have ALL of your details.
I am trying to send you in right direction.Talk to the counselor and you will definitely find some way out for this.
Dont hesitate to rever for any further assistance.