His grandfather is a devout Buddhist.

他的爷爷是一个虔诚的佛教徒。

He is a holy Buddhist.

他是一个虔诚的佛教徒。

She indicated that she was a Buddhist, not a churchgoer, but she was still willing to support our mission of serving the community.

她表明她是一位佛教徒，去教会，但支持我们服务社区的目标。