juvela
Riding a '38 Autocycle Deluxe
If the bike was a Sears it would have a Sears head badge. Most likely the same for Pennys, Formost. Looking at your brother's bike there is some writing on the oval in the head badge. Can't read it but it could be Formost? or Penguin? Due to the Penguin head badge and the early Huffy model name Penguin, this might have been a huffy imported piece for maybe Grants, Kmart etc. where the bikes were not rebadged with a store name.
-----
Thank you!

thanks also to CL for locating these adverts
all the examples illustrated thus far appear to be built with ashtabula type chainsets which would rule them out, in fairness some of the images are indistinct in this regard
one slightly unusual feature visible on both CL's cycle and that of the brother is the large rectangular Penguin transfer on the head tube over which is mounted a metal Penguin headplate
in the image of the brother's machine we can clearly see that a wedgebolt passes through the head of the non-drive side crank arm; this, when combined with the large dustcover visible on the adjustable side of the bottom bracket certainly indicates a Thun type chainset
AFAIK Huffman built no machines with Thun type chainsets but me Huffman savvy be quite thin
if the cycles have any Huffman relation it would seem to be a case of them being produced by a subber
the Huffman experts will know if this was ever done
the forum has had a a good number of discussion threads on juvenile bicycles which were house branded and produced in Europe
of the threads am able to recall do not remember any convertibles amongst them but am sure have not read every such thread
CL could try searching the forum archives with phrases such as "German convertible", "German made convertible", "Dutch convertible" or "Dutch made convertible"
-----