I will not comment on the validity of the request or the site, although it does appear to be a legitimate site and request. If the RedCross needed such help they would/should request it through normal channels.
If you wish to volunteer for the RedCross...CALL the REDCROSS! (1-800-help now) or visit their site http://www.redcross.org/
or check this one:
In Texas you can call 211 to reach the HHSC/United Way hotline for donations/help/request for help etc...
San Antonio is providing shelter and help for up to 25,000 refugees right now, so I feel I may be a little closer to the problem then others...BTW : I work for the Texas Health and Human Services Commission(HHSC) I think my sources are pretty reliable.