Sleep Deprived

Why doesn't Tyson sleep at night?  Why did God spoil me with Kayden?  Kayden slept through the night at 4 weeks old!  Tyler and Tyson---not so much!  At about 11 weeks old, Tyson was sleeping well.  9:00 until 6 or even 6:30.  Now, he's up between 12 and 1, then again at 3, and 6.....ugh!  I will take any help I can get.  Advice?  Encouragement?  Drugs?????

P.S.---yes, I get up with him every night.  Me.  Not his Dad.  Don't even ask....