No it is definitely not strange for a family friend to to publicly defend them, this family is in enough pain with loss of a small child and they are being vilified for their family situation and suggestive conspiracy theories are also hurtful. They believe he has wandered off, not taken. This is their opinion, which they are entitled to. they may not be able to bring themselves to believe he was taken, which would be a far worse secnario than him wandering off.
What would be strange is if their friends did not publicly support them.