House property related query

Yes he can , I will try to find some source for reference

Interest on self occupied is limited to 150k but of let out property is the amount of interest which may exceed 150k. Father should charge some rent from son to get more deduction of interest

yes the father can take the benefit on interest on loan, and he has to consider any one of his property as deemed to be let out property, if he consider this new flat property as deemed to be let out property, he will show it in an income from house property in the proportion of his ownership in the new flat and will get standard deduction of 30% from that, in thihs case he will get interest benefit to any extent, but the interest will get divided between him and his in the EMI proportion.