I am married to a child

Not that this is news to me but it hit me in the face AGAIN that I am married to a 48 year old child.  A little backstory--DH has been in Houston since September 1.  His company has properties there and 9 of them flooded so they sent him down there to head up the fix-it project.  It could be 4-5 months.  I gotta say--I was thrilled when this happened.  We have been talking about separating for a long time.  Our oldest son has been in Costa Rica on a gap year since Sept 16 so it's just me and the 16 year old.  And we just found out the owners of our building are not renewing leases because they are going to rennovate and reconfigure so we have to move by June 15.  So we spent our 22nd anniversary on October 7 talking about whether we would get one apartment or two.  We do not see eye to eye about parenting at all and that has been a HUGE thing the past five years as our two sons got oder (one is 16, one is 18).  So last weekend DH was up here from Houston for three days.  The 16 year old had a marching band compettion 90 minutes away and we actually went together and had a terrific time.  I had a glimmer of hope.  I should have known better because THIS weekend I got the same sullen, not listening, out to lunch person that I want to separate from.  I have asked him for the past, oh, 6 months to dismantle the fishtank which has been empty for months.  Still not done.  And instead of having the 16 year old do his homework, they sat at the table and played games most of yesterday, and then when I insisted the the child do his homework, DH says nothing and spends the rest of yesterday and today barely saying a word.  What is that?  The minute there is any whisper of conflict he just retreats.  I called him on it twice and he denies it, but seriously.  Grow up already.  The child has homework.  Perhaps put the games aside and, oh, be a parent and insist he do it for gods sake.  So that glimmer of hope went poof.  When will I learn.