Inform your Dad that you agree with his decision and the weather is too nasty to ride right now...and that you and he should be spending that time ASSEMBLING that Ebike in a comfortable indoor setting so that you'll be ready by Spring! Remind him of the joys of bonding over a father-and-son project etc etc...
God I love being 42 and single. Only bonecrushing poverty, lack of time and nowhere to safely weld stand in the way of MY Ebike!
(and skill, and patience and...)
At least I found some nice sturdy 20" wheels last week ( $5 Goodwill mountain bike with fused chain broken shifters and ruined brakes, but GOD the wheels were worth at least $70 apiece). Inch by inch...