Character mistake: At the skate park, Thor said he wasn't into girls because "girls are a distraction." Thor was interested in going to Soren's party because a lot of the popular boys were going to be there. When the "spin the bottle" landed on Thor, he said he couldn't kiss Brixlee and went upstairs. Hannah and Lily came home and told Thor it was OK that he wasn't ready for a kissing party and still had a lot of time before becoming interested in girls. Max previously told Thor that he wasn't as mature (sexually developed or undergoing puberty). Therefore, Thor's statement in the cafeteria about his new earring - that he "wasn't going for cute", he was going for "sexy and hot" - was incongruent and incompatible with his character.
Character mistake: Lucas says he loves "Ascension, rules, and anti-drug campaigns", so would not be likely to encourage Max to go to Soren's party after his father grounded him... or ask what his father would do about it (double-ground him?). Even though Lucas tells Max that he has "grown a lot" in the two hours after getting home and talking to his parents about all that happened that day (which they didn't believe), we aren't told in what way(s) he has grown - but it would not be favoring violation of rules. Also, Lucas later tells Hannah and Lily at Soren's house that he loves "Ascension, rules, anti-drug campaigns, and grilled cheese." This indicates that his view on rules has not changed, reinforcing the assertion that it was out of character for Lucas to encourage Max to go Soren's party while grounded.
Answer: Max's dad probably over-reacted out of anger/rage over the drone and destroyed room and might have made changes after he cooled off. Plus, it was meant to be humorous. A "month in the hole" was immediately imposed; no more birthdays, holidays, summer, etc. would refer to after the month in the hole. Max's dad did not say he couldn't attend school-related events, such as the "Rock of Ages" show. Parents are supposed to give their kids unconditional love. A father can continue to love his son while disliking his behavior. Max's dad may have been unduly harsh (again, out of anger), but he still loves Max - which shouldn't be depressing. I don't think Max's dad said he was grounded for life, just grounded. However, Lucas told his parents that Max was grounded for life - an exaggeration.
KeyZOid
So, even after being grounded for a month, he can't celebrate his birthday or summer vacation?
Not necessarily. Max's dad said those things in the heat of the moment. Although it is possible that Max's dad meant what he said (at least at the time), it isn't probable. The severity of the punishment given to Max was a reflection of how angry Mr. Newman was. A proud and loving father who tells his son "I will always love you..." is more likely to forgive Max so that they can return to their good father/son relationship.