First of all, sorry for your loss.
Since you’ve mentioned he died at home.
Hospital won’t issue you the death certificate.
1. If the area you live is urban,you’ll have to go to the nagar nigam office.
2. If it’s a rural area, you’ll have to contact the secretary (VDO) of that area. And he/she will issue the certificate.
If it’s the 2nd case, i can guide you further.