Visitor Visa for Mentally Challenged Sibling

[abhishek_rc6]

I intend to apply for a visitor visa for my Father (66 yrs) and my sister (25 yrs) who is mentally challenged and dependent on my father. My mother passed away a few years back. I have been reading on some of the other forums that chances of Visa getting rejected for a mentally/physically challenged sibling are high. Is that true? Will anyone be able to shed more light on this, and suggest me on how to establish the fact that she will only be visiting with my father (being dependent on him) for couple of months and does not intend to stay back.

If someone knows of any other resources that has more information on my situation, please let me know. I appreciate all your help in this matter.

Also, is it possible to go together as a family for the visa interview in all the categories (H1B, H4, B1/B2)?

Regards,
Abhishek

[immihelp]

1. It is very subjective. Therefore, hard to say.
2. No.