I take tarps and make them into BBQ covers regularly. They last, waterproof for years.
I heat seal them before and after sewing with a cool iron. Sometimes you have to play with it on scraps till you get the right temp.
Sewing needle holes really don't make a difference as far as I have seen.
If you want to do this for your friend, it will buy her a few years on a replacement.
MaryKatherine