First, I would try what V. said which is helping him learn to sit down on his own. Second my daughter is doing the same thing, this being my second that has done this I do know that staying in and there and lightly holding her down until she settles helps. I mean lightly, nothing that might hurt him or smother :). they eventually do get frustrated with you holding them still and start to cry a little but they also wear themselves out in the process hahaha and that helps settle them too. I am starting sleep training with my 9 month old and I know how daunting it can be, just stay strong with your resolve and remember that this is only a season. That's my mantra haha helps me to stay sane in those insane moments, best of luck mama!!