My parents finally got their visa issued! They had their interview on Jan 8, 2018 and we were asked to submit DS-5535 a week later for my dad only. I noticed updates almost everyday for a couple of weeks and then it was nothing. They were issued visa a week ago. For what I have seen, for parents it is a quick process andDS-5535 is not a common ask, but either way, we had to go through that wait regardless.
I wish each and everyone here the best of luck and I hope your wait ends soon!