Those are totally the letters my daughter has trouble with! and also L. It is also because she used a pacifier too long - especially at night. At the time I was going through the bomb and all this crap so the pacifier was the least of my concerns.
I will check the internet for some tips too but her speech teacher from school has also given me tips to tell her like "your tongue should peek out now or not peek out". She practices hard words while looking in the mirror which the speech teacher thinks is a good idea.
THANK YOU JOB!! So good to hear that your nephew made it through okay
---- M 39 H 35 D5,D4 M 4 T 9 ILYBNILWY 5/18/11 Left 7/11/11 Divorced 12/1/13