I may explain this poorly, so feel free to ask clarifying questions.

I have my homelab setup, and you can access services at service.domain.com only on my network or on my Tailscale tailnet.

I use a pihole for my DNS, and so does my dad.

Would it be possible to install Tailscale on his pihole (or elsewhere) so that his entire network can access my services (ie service.domain.com) but not route all traffic over my pihole and still use his?