Efficient way to block and unblock a contact regularly

[dhworph]

I have an aging parent who periodically calls me at a high rate, say 10 times in a minute. I still need to maintain contact with them but would like to have a way to quickly toggle blocking their calls and texts. Sometimes I'm at work and I don't want to have my phone on silent, but need to stop these repetitive calls at times.

Android used to have this capability built in to the phone app but it now seems to be gone. I'm on a Nexus 5X. I think I may be a couple of updates behind though, but the option I am talking about existed about two years ago or longer.