I'm trying to figure out how to translate the idiomatic expression "Bless his (little) heart" into German. The general sense is: "He meant well, but, wow, was that ever dumb!" I don't think the literal translation segne sein Herz will work here.
I would translate it as:
Er hat es ja gut gemeint.
He meant well (but).
to quote the other response:
Der Arme hatte es gut gemeint.
Es war ja gut gemeint.
It was meant well (but).
I'd never use 'Gott' in that expression. God no. :-)
Less friendly: Herr wirf Hirn vom Himmel. More friendly: Er/Sie hat noch viel Potenzial.
It will depend; as a parenthesis of sorts "Gott segne ihn" should work. If you want a full sentence, I'd suggest "es war ja gut gemeint, aber ... " oder "er hat es ja gut gemeint".
Do you have a fuller example?
How about ending it with "..., der Arme" or something along those lines?
I would translate this example of @aeismail
"He thought he could iron his pants while wearing them, bless his heart."
Er dachte er könne seine Hosen bügeln ohne sie auszuziehen. Gott hab' ihn gnädig.
However, Gott hab' ihn/sie gnädig only fits if the person is dead or is very close to death.