thanks all for ur support i ll try to follow all ur suggetions... thanks alot..

The five year old should be spoken to firmly but gently. Show him all his past pictures which will probably have him with his thumb in the mouth and maybe others where his friends don't. It will need gentle and firm talking but no force. The one year old is much easier. Here also talking and guiding even though you feel they don't understand you will be surprised how much they actually do understand. So gentle and firm statements. The older one can be recruited into being a role model for the younger sibling. They can actually feel very important if given the role of a role model.

Femite is the best way to get rid of the habit.. and it is totally harmless.. ur child vl cry a lot after sucking, then give Kuch Meetha to lessen the bitterness of Tongue.

try to convince child thumb is to say thumbs up.. not for licking it's nt hygiene..try Neem oil if nt worked femite lotion works