4year old used F word at school and lied too

Last week my son’s teacher told us that he has picked up the F word from another kid in the class. Today he bumped his head with another kid and used WTF. Upon asking by the teacher he said he learnt from his elder brother (he’s autistic,doesn’t speak). As parents we are concerned that after few months in school he’s using bad language and is also lying. What steps should we take? via /r/Parenting https://ift.tt/2S5fwdk