Since joined Al Nassr last three season ago, Cristiano Ronaldo and his family adopted quit well with new environment, new weather and new culture exactly huge difference with European countries. Ronaldo very difference with other European player get difficulty for adapting well at Saudi Arabia and most of them just stay for one season only such as Henderson. Talking about possibility for Cristiano Ronaldo scoring over 1000 goals I don' think its difficult so far he scored 938 goals, regarding his consistency performance at Saudi Pro League believing with his potential for next season will reach higher scorer in the world by scoring 1000 goals in his career.
Talking about Ronaldo reaching one thousand goals, I think he will definitely achieve that in two seasons to come, that's this season we're about to enter now and next season. As you said that he already has 938 goals which is true, he needs another 62 goals to get to 1,000 goals. He needs to average 31 goals each in these two seasons for both clubs and country across all competitions to achieve this of which is very visible and achievable for him.
Cristiano Ronaldo is already 40 years, two seasons he will be 41/42 years still playing important matches. This time of his carrier is no longer carrying the team but having interest of making history. Ronaldo will be needing 30+ goals per the two seasons, not a big number for the goal scoring machine he is, Ronaldo making that history gives him a cool down to retire eventually, i am sure that is the reason he still plays professionally.
Scoring 1000 goals gives him the record of highest goals scored by a player professionally, it will be a hard record to break by any player, now that football is no longer how it used to be, player this days hardly makes 40+ goals a season and how quick players retire before age.