What is your reason for donking the river?? You don't give him the chance to bluff the river. If I take this line I am definitely x/c the river. As played I would fold to that shove because I don't think that he has worst value hands to shove here, for example I don't think that he shoves AK/AJ/A8/A7/A4. He will only shove with sets and straights but I don't think that he has 65 in his range. Sorry for my english.

unless he is a loose reg then 65s shouldnt be in his range here. that being said i don't think we can call this bet and expect to be ahead here. x/c is a superior line. checking will keep his bluffs/ thin value range in, which will be more profitable. maybe if he sizes down to 1/4 pot we can think about x/r.?