Not as friends, no - Umbridge would serve her purpose and likely have a place in Voldy's ranks (after all, in the future where Voldemort won she was still around as the Headmistress at Hogwarts) but I doubt he would call her a 'friend'.
I feel like voldemort wouldn’t like the fact that she acts all innocent and find her kinda annoying. Also he’s a psychopath and i don’t think he can feel emotional connection to people. I don’t think umbridge would love being bossed around by voldemort, she likes control
