1) it is illegal to use deceased parents ATM card to with draw money from his account
2) in case bank or legal heirs files complaint with police you would be in serious trouble .it would be theft punishable under section 379 of IPC for imprisonment upto 3 years or with fine or both
3) it is better to redeposit amounts with drawn from the deceased parent s account
4) if deceased parent did not leave any nomination you have to apply for succession certificate from court to realise money lying in deceased account