How to handle a co-author who doesn't reply any more?
if I simply remove this co-author, put in acknowledgement and submit to a journal, will it initiate any future problem?


What did this person contribute?


You indicated before that many of your "authors" contributed only English help. If this is the case, then (I would argue that) they should never have been given authorship at all. If that is the case here, then I anticipate no problems with what you propose.
If this person made substantial academic contributions to your article (as defined in your field), then you must give them the chance to be listed as an author -- an acknowledgement isn't good enough. My view (and others disagreed in the previous thread) is that after 10+ years of no progress, you have a responsibility to get a "yes, list me" or "no, don't" before proceeding -- you're not in regular contact, so sending an "opt out or else" message isn't good enough.



  Can it be overcome at that time?


The only problem I can foresee is that many journals don't allow you to add authors after acceptance. (And of course, if this is mostly his ideas/work and you publish without giving him authorship, that could be considered fraud -- but I sort of doubt that is the case here.)