My friend wants to help him because they are very close, but he wants to know if there is a way that the deleted wallet can be recovered on his phone. He does not have the seed phrase anymore.
There should be a chance, but if he keeps on using that phone ever since, the chance that he can recover it intact will just drop.
So, inform him to shut it down ASAP.
But unfortunately, you'll need an expert on the recovering data from a phone's root storage.
Doing it himself/yourself will likely damage the recoverable data even further if the one's who's doing it doesn't know what he's doing.
And to reduce the search area and to lessen the false-positives, you'll need to know the wallet's original path which could be troublesome if it's closed-source.
This can be skipped by searching the whole storage though.