If you want people around you to be motivated, be their fan.
Cheer for them, clap for them, believe in them. Tell them they will be successful. Find what they are good at and nudge them. Promote them, advocate for their cause, put their work forward, write them references, and be their marketing department.
Particularly when things are not going the way they were expecting.
We are very good at being fan of political parties, sport clubs, divisive issues, social groups. And for some reasons, we are very bad at being fans of colleagues, team members, managers, partners, friends, peers.
Start being a fan of the people that are important to you. Your world will change.