Since this is a father - son transfer, it qualifies for an intrafamilial transfer. No roster restrictions and should be fine as long as it isn't an "assault weapon" with a Shield, seems unlikely. Because it is a transfer across state lines, federal law requires use of an FFL. Find a competent ffl with reasonable fees, etc. Look it up on the net, there are DoJ and Calguns articles, etc., which go into more detail.
Possible problems? "Pandemic" related processing delays have been occurring beyond the usual periods. And I'd expect ffls, etc., are stupid swamped right now. In the past during these riot conditions, I believe some cities may have shut down (or tried to) firearms sales, which is a different issue. Nor am I familiar with current "lending" provisions under state or federal laws. there's a lot to be said for checking things yourself at reliable sources beyond just internet forums.