I may first cite the excerpt from Netaji's book The Indian Struggle, in which he argues that Savarkar was only interested in strengthening the British Indian Army and nothing could be expected from him, as the leader of the Hindu Mahasabha, by then for the cause of Indian freedom (you can see the exact page here - https://archive.org/details/indianstruggle1902subh/page/384/mode/2up; Netaji, as the writer of the book, refers to himself in the third person as "the writer")-
"Mr. Savarkar seemed to be oblivious of the international situation and was only thinking how the Hindus could secure military training by entering Britain’s army in India. From these interviews, the writer was forced to the conclusion that nothing could be expected from either the Muslim League or the Hindu Mahasabha." (emphasis mine)
Next, citing Netaji's radio broadcast dated 31st August 1942 (https://www.myindiamyglory.com/2019/05/11/azad-hind-radio-broadcast-by-netaji-bose-on-august-31-1942/?fbclid=IwAR3ghNxMP3bAEv9rc3VwN6TiJeBFbZQU3wKwt6hrgoL7EqpfEuB7PnvDy_4 - unfortunately, the copy-and-paste option is not there), he reiterated his stand, requesting Jinnah and Savarkar to stop thinking of seeking concessions from the British Empire, saying this empire won't last and only those who as of then contributed to the cause of freedom would be remembered in history! He even praised as nationalists the Majlis-e-Ahrar and Jamiat-ul-Ulema.
I also know that many Hindu rightists claim that Netaji praised Savarkar, calling him ‘Veer’ (that would be quite a U-turn) in a radio broadcast in 1944 for sending recruits to the British Indian Army, who, on being taken as POWs by the Japanese, get recruited in the INA, though such a statement, even if true, sounds more sarcastic! But as Hindu rightist intellectual Aravindan Neelakandan has admitted (https://swarajyamag.com/books/savarkar-ii-by-vikram-sampath-completes-the-journey-of-a-man-misunderstood-by-most) -
"For example, there is an Azad Hind radio broadcast dated 25 June 1944 that Keer mentions in his Savarkar biography.
Many have quoted it as proof of Savarkar having the latent and strategic revolutionary in him and despite his assurance to the British, he had actually envisioned the INA situation and propelled Bose towards that end.
However, subsequent research by Bose scholars could not authenticate this speech." (emphasis mine)
Neelakandan tries to argue that it could still be factual, but there is no evidence of the same, but the radio broadcast I quoted is completely documented with the full transcript available; so, for Netaji to have contradicted himself does not add up, and something unprovable shouldn't even be up for discussion.
BJP-supporter Chandrachur Ghose also acknowledges how Bose, as Congress president in the late 1930s, while appreciating Savarkar’s pre-Andamans role in the freedom struggle, opposed Savarkar's Hindu Mahasabha strongly (https://theprint.in/opinion/subhas-chandra-bose-wasnt-anti-savarkar-heres-how-its-more-nuanced-than-you-thought/810505/)-
//When Bose asserted that only Congress should represent India in any future Round Table Conference, Savarkar protested. The latter argued that only the Mahasabha could claim to truly represent the Hindus, pointing out that although the Congress had won most of the Hindu seats in the previous elections, it did not contest the elections representing solely Hindu interests.//
//Bose’s criticism reflected his approach towards the communal problem, highlighting the difference with the Mahasabha approach. The Forward Bloc argued that ‘The Hindu Mahasabha has been doing incalculable harm to the idea of Indian nationhood by underlining the communal differences—by lumping all the Muslims together.’
It also mentioned that ‘We cannot oblige Mr Savarkar by ignoring the contributions of the nationalist Muslims to the cause of India.’//
Indeed, Bose’s great escape from house arrest to lead the INA wouldn’t have been possible without the help of nationalist Muslims from NWFP like Mian Akbar Shah, who were the first to host him, risking imprisonment or even death at British imperialist hands!
Further, even later, in a speech he delivered in January 1940 (before he left India to lead the INA), he praised the Ahrars, a Muslim group in Punjab, for rising against the British when the Congress leadership was deliberating (he had left the Congress by then, and he praised the Ahrars in the radio broadcast I first cited), and said of Savarkar and the Hindu Mahasabha–
“Nevertheless, there are people-and stay-at-homes at that-who do not scruple to cast aspersions on the patriotism of Indian Muslims as a body.”
