You are doing the best you can, and are using educational sites. Don’t beat yourself up!
Some additional ideas: use Letter school or iTrace for some handwriting practice. Log on to Storytime online or GoEpic! and have him listening to books online.
If you have play dough (or can make some with an online recipe), that is always good to strengthen fine motor skills in hands. Just playing with the dough is fine, but you can always have him roll it out to shape letters and numbers.
Stay positive! You’ve got this!