Option 1:

Hope hierarichal channels are implemented which would allow you to add participants to a channel off-chain. Or wait for eltoo

Option 2: If you have a Lightning channel, you could buy your friend inbound liquidity through some LSP like lnbig.com. But keep in mind lnbig (and other LSPs) seem to charge quite a bit these days because of high on-chain fees. Even a 100,000 sat channel costs $14, when a few months ago I got one with like 500,000 sats for around $3-4.

I would have recommended Phoenix, but to get a large channel you'd have to transfer a fair bit of funds to him first to open the channel, and then transfer it back I suppose