I wouldn't be too sure it's a Western flyer, nor positive ID on the badge, especially that it has a somewhat triangular appearance in the photo.
And it's the tank that's most different than all off known CWC paint schemes. The pinstripes on the fenders are thicker than those shown on western flyer indicated too. It has thinner stripes than your dad's bike. That thicker stripping is typically performed when CWC used 3 colors in it.
It helps to understand what The Cleveland Welding company did with bikes. Their own brand was 'Roadmaster' and they produced some of the most colorful bikes and contrasts in 3 colored wide pin stripping. CWC boasted about more than 100 different kinds of badges used too. Western flyer badge was just 1 of those 100+ but, also issued in very large productions.. Who knows what, other than typical roadmaster and western flyer/auto badges 100+ looked like.
Regardless, above all; what badge or fender painting, it's your dad's tank that's unique, even rare or, not in today's market place, other than your photo, known to exist.
For all of these reasons, plus CWC's 'Shockmaster' spring fork that causes the likelihood, it could be a special, CWC Rodsmaster, created special order by Buick or GMC's promotional dealer item.
However because the paint scheme on his tank is virtually unknown, until you can find an advertisement, a better photo or this tank's provenance, other than your grand father's got that 49 Buick Roadmaster right there too, you'll never discover exactly just what your dad had other than, exceptionally special, unique and current existing market or known to exist; a '1 of a kind'.. Not to leave out, the area in center of tank almost looks like or faint impression it's got a CWC 'roadmaster decal.
I.E.
You might to be able to find the original parts to build this bike, in good paint or have an expert repaint parts but not that tank's paint scheme. Not without a clear photo of both sides, and what the heck is on the badge. And the stripes on the frame might be 3 color wide stripes too.
r
Jeff54 - Great eye. Yes, he mentioned that was his dad's new Buick Roadmaster in the driveway behind.
BTW I'm not an 'Expert' or 'know it all' there's many CWC collectors, which also I am not. Just good at research. and dig cwc's use of colors in harder to find fashion . [wink]