Honestly, the experience is what matters - not the $$.
The $$ will be what they’ll be. It sounds like the roles/firms he’s applying for will be well aove $20 an hour - but I would use $20 an hour…just in case…so he’s not screened out.
If they pay their interns $40, they’ll pay $40.
But at this point, getting experience is what matters - not if he makes $30 or $20 for 12 weeks worth of work.
That’s truer today than prior - because you need an edge when applying for full time jobs - and an internship gives you an edge.