Betta fish very sick

Question
My mom's betta is very sick.  She changed his water yesterday and he became almost listless sometime afterwards (maybe less than 2 hours but we're not sure).  His swimming is rather jerky, and he stays on the bottom and lays sideways sometimes.  I may have figured out what happened but we don't know if there is anything we can do about it.  My mom cleaned his bowl with soap.  I'm guessing there was still some in there, not a lot of course but enough to make him sick.  Is there anything we can do or is it too late?  We have him in the small container she uses when she changes his water and need to change out his water again to make sure it is soap free.  Please let us know asap if you think there is anything we can do.

Answer
You should NEVER use soap, as you are finding out the hard way.
Did she use a chemical to take the chlorine out of the water?
The best thing to do is put him in fresh water, preferably with oxygyn and a filter.
Nothing more to do but wait and see if he recovers.  Good luck!