When a loved one has passed away their online presence may still have life. Below are some helpful tips on how to either manage or close a loved one's social accounts.
Twitter does not have an option to oversee another's account, regardless of relationship. You may request the account be closed using this email address: privacy@twitter.com
Instagram's options are similar to Facebook insomuch that you may request the account be deleted or you may request it to be memorialized. To do either, visit help.instagram.com then choose "Privacy and Safety Center" and then "Report Something" and finally, "Other Types of Reports". This will bring you to a help page that will further explain your options and how to implement them.
LinkedIn has an electronic form on their site that you may notify them of your loved one's death and have their account removed. This form can be accessed here or by going to help.linkedin.com and typing in the search bar "deceased".
Google and Hotmail both have options to gain access to a deceased account, provided certain requirements are met.