Did Kaine Horman care more about Terri Horman's older son than he cared about Kyron?

More I think about it, the more inconsistencies I see in the Kyron Horman case.

Kaine Horman stated that he sent Terri Horman's older son to live with his father because "he [her son] and Terri butted heads" and argued all the time.  Kaine claims he had to protect Terri's son from her, and that it was in her son's best interest to ship him to live with his father.

Kaine Horman stated several times during interviews with the media that Terri was drunk every night and had an alcohol problem.  He also stated she was on anti depressants and had postpartum depression.  If Kaine saw a problem with Terri that he sent her son (from a previous marriage) to live with his father, why did Kaine not allow Desiree to have custody of Kyron (like she asked him for in 2009) to "protect him from Terri"?  It seems if he cared enough about Terri's son from a previous marriage to protect him then he would have cared enough about his own much younger biological son and want to protect him as well.  

Not only did Kaine refuse to send Kyron to live with  Desiree even though he claims Terri had a problem with alcohol and depression, he also allowed both of his children to be regularly driven around by someone he claims was a depressed alcoholic.

If Terri was as bad as Kaine is now claiming and if Terri hated Kyron as much as Desiree Horman Young claims, then Terri, with Desiree's help, would have been able to convince Kaine to send Kyron to live with Desiree "for Kyron's well being" after all, if Kaine cared enough about Terri's older son to send him away as he claims, then he should have cared at least the same amount about Kyron.  

If Terri wanted to get rid of Kyron, she could have worked with Desiree to help her regain custody.  Instead we are suppose to believe Kaine when he says Terri was a falling down drunk yet planned a kidnapping and/or murder that numerous law enforcement agencies have not been able to solve in over a year even after spending over a million dollars investigating it.