I think this is a good example of why you need to set your wishes out.
I reply on a lot of Will/Gaurdian making threads, because I've seen how people change, when left with an inheritance and/or power over burial etc. I'm 48 and I've worked in end of life/social care, so come into contact with a lot of families.
I'd like to give some of his behaviour the benefit of the doubt, having been Widowed myself, but the remarks about making love to her ghost, was disgusting.
""I think it would be weird to use the account to like other people's posts though""
I agree. I thanked people on a close relatives account and used it as a way to announce funeral arrangements (and the death after contacting people that I could). I haven't shut it down, yet, but I constantly deactivate it.