No way that's the logic here. If the prosecution did such a bad job then letting him testify only adds risk. There must be something they feel they need to get out onto the record for some reason. It could just be as simple as the lawyers doing some CYA, e.g. if there is a risk of 2nd degree charges they may try to reduce the charge to 3rd degree or negligence through his testimony. Again IANAL just seen enough TV.
It humanizes Kyle by having him take the stand.
To a certain extent. But regardless of how many times a jury gets told that they should take no meaning into a defendant not taking the stand, it's been shown that juries still consider it. Letting him take the stand probably outweighs the risks in the defense's eyes.
As much as I am against ANY defendant taking the stand, these defense attorneys have done an OUTSTANDING job in this instance I will trust them!!