Generally, you would attend the funeral. You have the history of the relationship from your marriage and assuming you maintained a relationship with your husband’s family since he passed, it certainly would be appropriate to attend.
As for if you are “still family” – that is entirely between you and his family. Usually, spouses are still considered part of the family for a period of time even following a death but this is different for everyone. I will assume that since you are questioning this it is because you are not sure of your place now, so I would plan to sit away from the family unless you are invited to sit with them.