Hi M.,
My kids have both learned to swim with lessons at the city pool by Red Cross certified instructors. Don't know if you have looked into that, or if it is available in your area. You might check it out.
Also, just to give you a little perspective and possibly make you feel better, my 11 year old was not truly comfortable in the water until he had had lessons for 5 years. I started him when he was 3 and he was so afraid of the water he would not dunk his head. I just kept working with him until he got it... several years later he swims like a fish without help anywhere at anytime. On the other hand my 7 year old took to the water the first year (he was also 3 when I started him) and swims beautifully, but it took him less time. I will enroll both of my children again this summer and this will be their 8th and 4th year of lessons. At this point their working on perfecting strokes, but it is important for me that they are proficient since we own a boat, a pool, and love to participate in water sports. One thing that made a big difference was swimming every day in the summer, either at home after we got the pool, or at the city pool. Practicing daily made all the difference.
Hope this helps, and good luck. Don't give up or lose heart because they will get it. :-)
S.