A player slips or falls during a point
A fall is not a let. Lets are for interruptions that have nothing to do with the players, so the rally goes on. After the point, an umpire may allow a short time to recover.
The point goes on
The rules give a replay for unexpected interruptions unconnected to the players. A player who slips, trips or falls is very much connected to them, so the rally is not replayed for that reason. If the ball bounces twice before they get up, the point is lost.
Time to recover
If something unusual, such as an accidental fall or being hit by the ball, stops a player carrying on straight away, the umpire may allow a reasonable time to recover, never more than 5 minutes. Proper treatment for an injury falls under the medical rules.
Safety first
If someone looks hurt, stop. In social games most groups simply replay a point stopped to help a player. That is a kind choice, not a rule, so agree it among the four of you.
Questions
Is it a let if someone falls in padel?
No. The rally continues. Many social players replay it out of kindness, but the FIP rules do not require it.